1998 Bonn L36 Intake, Head, or worse problems? pics included

[Taurus1979]

So I've been lurking here a while now and wanted to be fairly knowledgeable about our issue and use the already posted issues to solve our problem. The problem we had right before this major issue was the security light. This forum helped us to get around that and it ran great for a few more weeks. Then there was one day it almost overheated but it was shut down quickly. We only had to add coolant this one time and it drove fine for another few days. Then of course it was the dreaded P0300 with bad hesitation intermittently under 50 mph. This persisted on and off for only about a week before she finally gave up. After throwing plugs, battery, sea foam, and other parts at the hesitation issue it finally hydrolocked one day after being shut off. It would not re start and eventually upon one of the attempts it made that awful sound of starting your car when its already running and three or four of the teeth on the starter were bent. My husband inspected the flywheel and saw no damage. We replaced the starter and some vacuum line that was cracked (from the FPR to the Throttle Body) and tried to restart, one clunk was all she gave and it hydrolocked. Taking out the plugs did allow the engine to be turned by hand. Then coolant did come out of two upon cranking, one in front (right side) and one in back (also right side).

So we tore into the intake and decided we might as well go deeper. There was a lot of fluid in the upper intake. Less in the lower but it was very ugly too. Of course the plastic elbow deals were broken as well. The tstat was also very sludgy and gasket was broken. It seems that rusty colored sludge has got into everywhere. Now we are down to the heads in front and I have uploaded some images. Considering the plugs were far far worse in back I can only imagine how nasty that one will be. Can just bad intake gaskets cause all of this? I will note that according to the code on the top of the plastic plenum it was replaced in the car in 2003. We just bought the car about a year ago for $2400 and it had 86k on it and it now has 104k. We kept up regular maintenance with oil changes, plugs, etc..

We don't really want to replace the heads. And I am not sure if images or a visual inspection can diagnose them as being bad but any input is very appreciated. This is my first post here so please let me know if you can't see the images.











I think my husband and I will be tearing into the back side later today. Thank you for any help and advice. This really blows. It's crazy how she was such a dependable ride then all of a sudden poop! lol

[MKMike]

Welcome to the forum.
Sorry your first post is about a serious problem.
Sounds like the previous owner didn't replace the LIM gaskets when the UIM was replaced.
This post has plenty of important details on the job http://www.pontiacbonnevilleclub.com/fo ... c3591.html
I'm no expert on the potential damage but I'll share what I do know....
Hopefully, the hydrolock didn't bend a connecting rod.
Not sure that the heads actually needed to be removed but, since they're off already you can check to see if the pistons are all coming all the way up.
If not, a rod has bent.
Not sure how you would know if the bearings are OK.
Also check the pushrods to make sure none has bent.
If coolant got into the crankcase, jack up the front of the car and drain the oil/coolant mixture out.
You'll want to change the oil a couple of times after it's back together to be sure all the coolant and any grit is out of the oil.

[Taurus1979]

Welcome to the forum.
Sorry your first post is about a serious problem.
Sounds like the previous owner didn't replace the LIM gaskets when the UIM was replaced.
This post has plenty of important details on the job http://www.pontiacbonnevilleclub.com/fo ... c3591.html
I'm no expert on the potential damage but I'll share what I do know....
Hopefully, the hydrolock didn't bend a connecting rod.
Not sure that the heads actually needed to be removed but, since they're off already you can check to see if the pistons are all coming all the way up.
If not, a rod has bent.
Not sure how you would know if the bearings are OK.
Also check the pushrods to make sure none has bent.
If coolant got into the crankcase, jack up the front of the car and drain the oil/coolant mixture out.
You'll want to change the oil a couple of times after it's back together to be sure all the coolant and any grit is out of the oil.

Thanks for your response! Well researching this forum has helped us solve the simpler issues so that's why I waited for a big issue to post. We may not have needed to go as far down as we have but we kept wondering how much deeper the sludgy stuff went so I am glad we did. It seems to be into everything so yes we plan on replacing many parts that may not be in need but while we have the room to work we might as well, such as water pump, radiator, and hoses. We will definitely follow your tips on checking the pistons and pushrods first as well as the info at the link you provided. We did get all the fluids out as soon as we could.

I am really hoping we can save her. I particularly like 3.8 motors. I have had Fords, GMs, and Chryslers with the 3.8 and while they are all different they all seemed to get upwards of around 250k at least. My 89 Olds delta had 330k and the frame fell apart but motor was still strong lol. So its worth the effort I think to attempt the major repair.

I have a had a friend who is pretty knowledgeable suggest that it looks like an additive may have been used to stop the intake leak which has now clogged up the gasket outlet points causing it to fail. Could this be what that orange goop is? We really just started seeing it appear in the reservoir and radiator over the last few times we have checked the fluids. It seemed to be right after we sea foamed through the brake booster. It was right before then that we started experiencing slight hesitation but we had no engine light at that point and couldn't get any codes to pop up. Is it possible that could have caused the goop to really break loose and travel through the system? I wish I would have taken pics of all the stuff in the manifold before we sucked it out with a turkey baster. There was a lot of orange goo in the crevices and the fluid was watery brown but smelled sweet.

[MKMike]

The orange sludge is what Dexcool turns into.
That--and the fact that it eats manifold gaskets---are the reasons people here switch to green antifreeze.
GM was sued over these things but their bankruptcy nullified many payouts viewtopic.php?f=18&p=225653
A good thing to do is to reverse flush the cooling system parts individually, as detailed here http://www.pontiacbonnevilleclub.com/fo ... 45&t=15064

Hope your Bonnie is up and running again soon!

[Taurus1979]

So the heads and piston gasket surfaces cleaned up well. It sure isn't a mirror finish like I have seen in many photos but its completely smooth. Only a razor blade was used.





The LIM however has two areas on the sides that are possibly a concern. Its smooth except for these two areas that show some reddish staining. It's not like gouges or scratches, not sure if this is a huge concern. We were advised to use gasket sealer and that it should be fine.





Funny thing, we had just decided against pulling the oil pan and just doing a couple more flushes. Well, it appears now that the oil pan is leaking at the gasket. I am guessing coolant ate it? We did drain the oil first thing but even after a couple flushes it still comes out pretty dark. So, I guess we are definitely pulling the pan.

We have ordered some of our new parts including a Felpro head gasket kit, water pump, metal elbows, new injector clips, wires, plugs, and other minor things. I do have a question regarding the brands of UIM plenums. I see conflicting reviews on Dorman and the ATP brands. I am guessing the complaints are likely user error as they all seem to mention cracking while torqueing.

Has anyone ever used a Magnum Gasket brand of UIM? I can't find ANY reviews on this brand but I am familiar with the company and they have a pretty good reputation. The part number for Magnum UIM is MA40001. It does have the double isolated metal sleeve. Here is a link to the pdf documentation on the Magnum UIM.

http://media.spicerparts.com/cfs/files/ ... e=original

I appreciate your tips and responses. I am trying to update here as we move along. We are doing this outside of work, school, kids, etc.. so sometimes it takes a few days for us to move on to the next step.

[J Wikoff]

Side note, try the tags that just have the IMG tags around them and not the URL tags. The URL tags don't work with our software.

[Taurus1979]

Thanks for the tip on the images! If possible I will go back, edit, and fix all the previous image tags as well.

So, as it turned out the oil pan was only leaking due to certain necessary parts being removed (drrp!) However, we said screw it and pulled the entire block. It was only like 20 more bolts anyway lol. Boy was she dirty! Dropped the pan, visually inspected everything, cleaned her up, and replaced the pan gasket with new one anyway. Thankfully, there was no gel material or metal bits in the pan. Yay!

It took 4 of us approximately 8 hours total to pull the bottom block, organize and label parts removed, clean it up, inspect it well, change the pan gasket, and re-install the bottom block back into the car. We also removed the radiator, definitely going to replace it. We also put in a new water pump. There were a couple breaks in that time period and of course a trip to the auto parts store.


I also discovered several messed up wiring connections. Some just needed to be cleaned and re-insulated but some were all frayed and damaged. A couple grounds were so bad I am not sure how the car was starting at all. Of course just prior to this, it really wasn't. I am guessing fixing these will help resolve many of the hinky electrical issues.

The heads also got new valve stem seals. So that is where we are at as of now. Hoping to get the heads and intake back on this week and then it should be small stuff from there. We have a list of things we need yet and of course a list of some small casualties along the way.

Casualty and misc list (LOL)



Oil pan removed




Before and after block cleaning




I think we are going to go ahead and order that Magnum Gasket brand UIM plenum from Rock Auto. I still haven't been able to find any reviews at all on that one but maybe I can be their first good Internet review. I am so excited to get to partake in this project. It's been an interesting bonding experience for my husband and me. I definitely have learned to appreciate his mechanical ability.

[redfury]

Like previously stated, Dexcool will gel up like that, especially if someone used antifreeze to fill it up that wasn't compatible ( most are formulated to work with all antifreeze blends these days ). You may find after reinstalling everything that you have to do a crankshaft position relearn. It's literally a 30 second process, but the dealership will want a standard rate just to hook up their machine to do it. Any shop can do this procedure ( or anyone that has access to a bidirectional scan tool ). If it becomes necessary to have it done, just throw feelers out there, I'm sure someone will be willing to do it for a 20 in their pocket for their troubles.

The nice thing about doing the tear down to the point you went is that you will know that you have new gaskets in all the right places ( I'd maybe consider front and rear crank seals as long as it's out as well ). Consider replacing the power steering lines while you have the block out as it will be way easier, and we all know that power steering lines are just a leak waiting to happen, if it hasn't already. Fairly inexpensive and way easier with the engine out.

Keep us posted! Everyone loves pics!

[Taurus1979]

So yesterday we did decide to replace the push rods. None of the push rods were bent from the hydrolock but our friend who is helping us pointed out that there were some groves and wear patterns on the ball ends that could have been causing the cold start tick I get in the winter months. I have noticed this is pretty consistent with other GMs I have had in the past. It isn't loud and always would go away after less than 30 seconds but I figure it always pays off in the long run to listen to someone who has more knowledge and experience.



We spent a lot of time examining the rocker arms and it was decided to re-install the originals. The wear patterns were consistent and all the moving parts were functional.



There is one area I will point out on the bottoms where the valve stem hits. There was one or two that had wider and rounded impressions but all the rest had centered and more vertical impressions.



Our friend said we really should just replace the rods and re-install the original rocker arms and so that's what he did. These rocker arm kits are crazy expensive! It's nice to have an experienced set of hands on something when you really don't want to screw it up. LOL

This is what is so conflicting about going this far into your engine. You come across so many things that you want to re place but are hesitant to do so. I imagine we will kick ourselves at a few points later on when we have issues in the future. I was not aware there are issues with the power steering lines but I agree these would be easier dealt with now. I am also pretty sure the cat is a priority as it likely suffered some damage.

I have read (somewhere in this forum I think) that soon after major repair was done that was a result of leaky manifolds, the person said that sensors started going out left and right. So these are things I am keeping in mind because if they happened to someone else it's likely they will happen to us as well. Not only did we have leaky manifolds, it's apparent we also had leaky valve covers as we have come across damaged wiring and soaked sensors as well.

We also found some weird jumper wires stuck in the fuse slot for the fuel pump( fuse box in passenger kick panel) and running all the way to into the trunk latch. No clue whatsoever why that is but I will save that for another thread and keep this one focused to the leaky manifolds and engine re-freshening (as Chilton's calls it).

The new plenum ordered from Rock Auto should be here by Friday so we are hoping to get things moving along over this weekend. So far the weather has been holding out for us but here in Iowa that can change drastically. Next week is looking pretty chilly.

[MKMike]

I'm all for preventative maintenance and for replacing things while they are much more easily accessed than after things are back together.
Kudos to you and your husband for all your work.
Not familiar with magnum brand manifolds, but that doesn't mean they're not good.
It must be very nice to have a knowledgeable friend around to chime in when any questions arise.
Hope you're back up and running smoothly soon.

[Taurus1979]

We received our new Magnum plenum from Rock Auto yesterday. Just out of the box it appears and feels much more durable. There are many areas which are heavily reinforced compared to the old one. Specifically, where ours has failed so I am happy for that.

New one on left / Old one on right



Bottom view of new one



Top view showing brand



Package included all the necessities and very detailed instructions




Hoping we get time to get a lot done over the weekend. The most intimidating part is the torqueing, especially since it's plastic . Thankfully we do have someone assisting us with this part. This is where I have read a lot of people eff it up. Fingers crossed!

[Jrs3800]

The 95-02 3800 Series II's loved to eat the ball end of the pushrods... The later 03+ 3800 had slightly higher oil pressure from the factory and were friendlier to the pushrods.. An oil pressure kit from Intense Racing or ZZP may be a decent idea for you, along with new pushrods.

[Taurus1979]

So, we got everything done and tried to start last night. Crank no start, pretty much where we were at before the motor hydrolocked. So I guess at least we must have put it all back right. It sounds literally exactly the same as before.

Everything that is necessary to start and run for a minute or so is back in. Theres a few brackets not in and no coolant but oil is in, plugs, and new wires. The plugs had just been changed before this but did get wet during hydrolock. 4 out of 6 plugs showed orange spark and 2 were blue. The spark across all coils were bright blue/white.


Right before the motor hydrolocked we checked the fuel pressure. All we could test was engine off and key on. Same as now but at least we can crank. Same reading, 30 Psi and it drops sharply to 23 psi during crank. I know it's low but would this prevent starting? We did replace the vaccum line and that double hose rubber fitting that goes from the FPR to the throttle body. It was cracked before all this, probably contributing to the vaccum leak.

We tried ether in the throttle body and it had no effect. Fuel comes easily out of the rail when you press the valve in. We drained off quite a bit and it smells like turpentine. We did replace the fuel filter before all this.

After several attempts it seemed like it wanted to start and it would do that poof sound and rumble thing, a couple times it almost started. But we gave up after about an hour of repeated attempts figuring at this point we were flooding it.

Removed the plugs to let everything dry out. Going to get new ones tonight just to see since these were coolant soaked at one time.

So frustrating after all this work. It must be a multiple issue problem. I put this video on You tube of our initial attempts to start. Thanks for any input.

https://www.youtube.com/watch?v=IcTcBvSmy5I

[MKMike]

Are you using Bosch spark plugs?
They have an exceptionally high rate of failure in our cars.
In fact the techinfo maintenance sections advises against Bosch plugs for this reason.

Since the spark was weak at the plugs but not the coil it is either the wires or the plugs.
With the wires being new and the plugs are not.
My vote is for bad plugs.
ACDelco are excellent plugs.

If new non-Bosch spark plugs don't remedy the problem....

Carefully check all ground points under the hood.
There are also 2 ground buses found behind each of the front kickpanels.
Many grounding issues arise in these.
viewtopic.php?f=19&t=30286

While 30 pounds fuel pressure is too low, I would think that ether into the throttle body would have started it up.

[redfury]

First things first, double check your spark plug wiring and routing...it's easy enough to put a wire in the wrong place, same goes for the injectors. I used color coded wire ties to ID where they went back to make sure I didn't screw up the injectors. If that all checks out, then I'd start with making sure you are getting spark near TDC at cylinder #1 to make sure your spark timing is right. Ether and proper ignition is going to kick the engine over. IF you have fuel, then you don't have proper spark or spark timing.

Fuel shouldn't smell like turpentine...you've got punky fuel. Get some fresh fuel and a new fuel filter in the car ASAP. I would also make sure that all of your valves are opening and closing by pulling the front valve cover and watching them as the engine is cranked over.

The fuel pressure is way to low though. Change the filter and check it again. IF the fuel went bad and clogged up the filter partially, that will drop fuel pressure and could damage the pump. Filter is cheap and easy enough to do and likely needs to be done anyway.

[Taurus1979]

We had NGK plugs in. We did get new ones last night but since we were still at the troubleshooting stage we bought cheap Autolites. It didn't work but that's probably because we discovered we had the rocker arm stand upside down, both front and rear.

Once that was remedied, it started right up! Smoked a bit for about 10 mins but that was expected. That dissipated pretty quickly and it drove great. Ran it for a while last night, mostly at idle, and made sure we had no leaks and bled the air out of the T-stat housing (a few times). So tonight we did the same thing and double checked everything and it ran even better! Drove it a bit longer this time.

Yes, we are putting new gas in for sure! Probably the filter again too. Are Autolite plugs that bad? It seems to pop right off with them, maybe we will leave them in for a while. NGK is usually what we use for all of our cars though. We also will be changing the oil right away. We put 5w30 in initially to clean things out, but definitely want to go with our usual 10w30 for daily driving. Going to keep a good eye on things for the next couple weeks.

The fuel pressure is still 30 with key on engine off but 42 during idle. So I am guessing we will likely be changing the FPR and pump soon. Better to do it now, winter comes to Iowa very soon. I think this car was pretty neglected when we got it.

Overall it seems to be increasingly, sounding and running better. Tomorrow I will be posting a YouTube video of how it ran at the very first startup compared to a couple days later. I will post the link here. It's a pretty apparent difference.

[MKMike]

That's great news.
Glad you figured it out.

There's nothing wrong with Autolite plugs.
They'll just need to be replaced sooner than platinum tip plugs because the electrodes wear out more quickly.

FWIW, the ACDelco brand is generally less expensive than the NGK brand--and they're actually the same plugs, just marked ACDelco.
Rockauto gives a forum member discount using the code from their post in the vendor's forum on Pontiac Bonneville Club.

Your NGKs should be good to reinstall when you need to change plugs.
There should not have been any damage from the coolant.

Fuel pressure of 42 PSI at idle is absolutely fine.
Perhaps the KOEO reading was from some air trapped in the gauge.
You have to bleed off the air and cycle the key a few times to get the highest KOEO reading.

To determine whether the fuel pressure regulator is working is rather easy.
First, check for any fuel in the vacuum hose to the FPR--even a drop is too much.
The hose should not even have a fuel smell.

Next, while the car is idling, with a pressure gauge attached, pull the hose off the regulator.
You should see an instant 10 psi rise in pressure.

[Taurus1979]

Thanks for the tips on the Rock Auto discount, we shop there a lot!

So we found this splice in this fuel line that goes from the fuel pump to the filter. Looks like some attempt was made to repair it but this is where it was leaking, just a little so it was barely noticeable unless someone happens to be standing near the rear at the time the car is shut off, only then do you get a whiff of fuel. Then you can see it from underneath as well if you watch while someone cycles the key on/off.



So my husband replaced it with this line... which eliminated the need for line splicing, not sure why someone would do that when this part is available. I can see for a quick fix but not permanent. This part was $37 at Advance auto.



With this new line the KOEO pressure increased to 34/35 psi and idle remained steady at 42 psi.



I do think we need a new FPR. We don't get the fuel spill from the regulator with hose removed but I smelled the vacuum line before when we had to replace it and it smelled strong of gas.

We are going to be taking the car out today for more than just test driving so we will be repeating some of these tests to see how things hold up after normal driving. I think we are really getting close to solving all the issues. The only other thing we noticed is that the metal AC lines are sweating a lot but the system was evacuated (shhh don't tell the EPA lol) when we pulled the motor so maybe its condensation because Freon is so low.

My husband also decided to paint the engine cover so here's a pic of that just because lol



Here is also the comparison video I posted to You Tube of the car running.

https://www.youtube.com/watch?v=oSMBklj ... b2-B-gUdbg

I sure appreciate all the tips and hopefully once we get the new FPR on we can call this solved! I think this poor car suffered a lot of abuse before we got it. Rarely have I seen multiple issues like this all fail at once.

[MKMike]

That's a great color on the engine cover!

The "half-fast repairs" that some people do gives one real insight as to why so many states require annual safety inspections!

Back when I was a mechanic, my all-time personal favorite was the idiot who used a wire coat hanger to put the tie rod back together and then DROVE several miles to the shop.

Much more recently, when I bought one of our Bonnevilles, the PO had repaired the rusted out fuel line with a piece of rubber propane hose and 4 screw clamps.

I'm very glad that this failed while it sat in my driveway.

As for the FPR, they may not leak much until the car has run for a few minutes.
You can start watching this video just before 2 minutes , then skip to the 4 minute mark to see what I mean..
https://www.youtube.com/watch?v=AKtR_yF7bi8

Super easy to change, with snap ring pliers being the only tool needed.

[Taurus1979]

We did go ahead and order an FPR but I want to try that test for a longer amount of time as suggested. The car ran really great today up until the old problem reared it's ugly head. This is an issue we've been chasing since buying the car about a year ago. We really thought the manifold leaking coolant was the issue but apparently it isn't. It's hard to describe and extremely intermittent.

From a dead stop, applying the gas, it will sometimes hiccup 3 times before it finally goes. It's not like a typical hesitation or loss of power. It's very loud, scares the crap out of you, and even the change in the cup holder, or butts in the ashtray, will fly out. It's pretty impossible to duplicate. It either does it when it wants or it won't. It doesn't seem to matter if the car is warm or not. No codes. No warning lights. Doesn't really matter how hard or light you apply the gas. The only consistent thing is that it only happens when you try to go from a complete stop. It never does this any other time. It can go weeks or months without doing it, which is why we always think we've solved the problem.

It's very hard to describe but it feels like as if the tires were being prevented from moving, then there's a very very loud thud thud thud, then it just goes just fine. It literally lasts for like 3 seconds, never any longer never any shorter. It did this only one time while driving today, at a stop light. I was probably at 30 stop lights and a few stop signs, but it did it only that one time. Not sure if fuel pressure regulators could cause this but I sure hope so. The vacuum line did smell like fuel again.

I would love to be able to catch this on video but you just can't predict it. Other than that it drove very nice at various speeds. All fluids were normal and for the first time since pulling the motor, the oil looks and smells very clean. Of course we did 3 changes in a row on it thus far since putting the motor back in. I think we are just going to park it until we get the FPR in the mail. We may do some more tests in the mean time but only at idle. It's not worth possibly damaging anything at this point. We've put a lot into it.