Years Later, Pontiac Wrangled Me Back Again!

[PhoenixStar]

Hi Everyone
It all started with a 1980 Trans-Am, then an 81 Firebird, then an 87 Fiero SE. I had them all for many years, loved them. Took a break from Pontiac for a long time, came to find out I really missed the "Driving Excitement", and yesterday that led me to my first Pontiac purchase in a long time... my new (used) 2005 GXP. I had wanted a SSEI Bonne many years ago, and it didn't pan out. And now almost 15 years later I own a GXP. I almost didn't consider the GXP due to the bad rap of the Northstar, and when I was researching, I found plenty of hate threads dedicated to it, specifically the head gasket repairs. Hopefully, i'll dodge the bullet, and my GXP will give me plenty of years.
I found my 2005 GXP very good condition, with 80k miles (over 16 years). Visually no signs of leaks or past residues on the engine... a mechanic looked at the motor from above and underneath and said it was one of the cleanest he's seen. There's a car fax report that shows only 1 prior owner, with an extensive routine/scheduled maintenance history. It runs beautifully, and shows no signs of abuse. It's day 2 and I love the car. The dash is lit busy red, just the way I like it, and the styling is well,Pontiac... just the way I like it.
I did have an issue already though, perhaps a false alarm? When I went to warm up the car this morning (I live in New England, it was 28F outside), the low coolant warning message popped up. After my stomach sank into a pit of despair thinking I just became the latest head gasket victim on day 2 of ownership, I shut the car off and popped the hood, the coolant level was perfect. I turned the car back on 2 minutes later, and the message was gone, and has remained gone for about 125 miles so far. Baffled, I looked this scenario up online. Apparently, even when new, the GXP would occasionally throw this message in cold weather, and go away minutes later, no big deal. Is this really the case, am I correct about this?
And lastly with what I described in the condition above, what's the likelihood that I'll be a victim of the head gasket issue, or is it possible to make it to 200k without that problem? My driving habits are highway miles, cruising with occasional WOT to pass other cars, but never abusive hard driving. Is this issue preventable at all? I know the internet is the dumping ground for bad experiences where negative always outweigh the positives, but are there more Northstar success stories than failures?

PS- Also I noticed my temp gauge moves anywhere between 200 and 1-1.5 needle width spaces past 200. Im guessing this is acceptable, and that the gauge is more of a dummy gauge than an actual temp gauge?

Anyways, glad to be back in a Pontiac.

[CMNTMXR57]

Most likely a simple ECT sensor.

http://www.pontiacbonnevilleclub.com/fo ... 47707.html

Yes, that is normal temp. Today's cars run hot for emissions purposes. So 200* - 210* is the norm as the fully open spec on LD8's t-stats is 206*. Also, keep in mind, the gauges aren't calibrated instruments.

[PhoenixStar]

I actually read that post prior to becoming a member here…there's lots of great info on this site.

[1oldman]

Glad you're back in a Pontiac, a Bonneville and a now a club member. - BC

[PhoenixStar]

Glad you're back in a Pontiac, a Bonneville and a now a club member. - BC

Thanks! I just hope I can share a positive N* story for years to come. Based on the prior history of the one I have, perhaps it's possible.

[CMNTMXR57]

Don't be like everyone else who jumps to the ultimate conclusion that it's a head gasket because...

I'm not saying it couldn't be. But start small first. 9 times outta 10, you'll find the problem and it'll be a simple/simpler fix and NOT that ultimate issue.

When it actually starts running overly hot or overheating, you get milkshake like coolant or oil, or you see tell tale signs of leaks on the block or on the ground overnight, then start worrying that it could be the worst case scenario.

For now, though, I bet it's a gunked up ECT sensor, which also is a common issue on many GM vehicles.

[00Beast]

When the HG's on ours (Now Clayton's) let go, it was pouring smoke out the tailpipes like Cheech & Chong had taken up residence in the back...

[PhoenixStar]

Don't be like everyone else who jumps to the ultimate conclusion that it's a head gasket because...

I'm not saying it couldn't be. But start small first. 9 times outta 10, you'll find the problem and it'll be a simple/simpler fix and NOT that ultimate issue.

When it actually starts running overly hot or overheating, you get milkshake like coolant or oil, or you see tell tale signs of leaks on the block or on the ground overnight, then start worrying that it could be the worst case scenario.

For now, though, I bet it's a gunked up ECT sensor, which also is a common issue on many GM vehicles.

Yep its running good now, no sign of leaks, drips, smells, or running hot. I'm not too concerned at the moment but I'm going to continue to monitor the coolant reservoir level for a week or so to check for low levels. I read somewhere that you can lose a bit of coolant from somewhere only while driving under load that makes it hard to detect loss.

I saw a post you wrote in 2012 saying that the 04/05 N* is either fixed or not prone to the gasket issue as prior years were. Is this still the case in 2016? Is it "fixed" with nothing to worry about, or is the chance of the gasket issue just "slightly less"?

[CMNTMXR57]

When the HG's on ours (Now Clayton's) let go, it was pouring smoke out the tailpipes like Cheech & Chong had taken up residence in the back...

[CMNTMXR57]

Don't be like everyone else who jumps to the ultimate conclusion that it's a head gasket because...

I'm not saying it couldn't be. But start small first. 9 times outta 10, you'll find the problem and it'll be a simple/simpler fix and NOT that ultimate issue.

When it actually starts running overly hot or overheating, you get milkshake like coolant or oil, or you see tell tale signs of leaks on the block or on the ground overnight, then start worrying that it could be the worst case scenario.

For now, though, I bet it's a gunked up ECT sensor, which also is a common issue on many GM vehicles.

Yep its running good now, no sign of leaks, drips, smells, or running hot. I'm not too concerned at the moment but I'm going to continue to monitor the coolant reservoir level for a week or so to check for low levels. I read somewhere that you can lose a bit of coolant from somewhere only while driving under load that makes it hard to detect loss.

I saw a post you wrote in 2012 saying that the 04/05 N* is either fixed or not prone to the gasket issue as prior years were. Is this still the case in 2016? Is it "fixed" with nothing to worry about, or is the chance of the gasket issue just "slightly less"?

No such thing. A cooling system is a closed, pressurized system. Any loss of coolant is due to 1) leaking and/or 2) burned in the combustion process (I.E. leaking head gaskets causing coolant to make it's way into the combustion chamber).

As to headgasket/stud issues, 2004/5's just aren't "prone" to it. That doesn't mean that it doesn't happen. Many still do as is the case around these parts...

When we say that early N*'s were a common issue with this, we're referring to pre-2000 versions. In 2000 GM put longer studs in and reduced compression slightly to reduce cylinder pressures, relieving some stress on the studs some.

[PhoenixStar]

As to headgasket/stud issues, 2004/5's just aren't "prone" to it. That doesn't mean that it doesn't happen. Many still do as is the case around these parts...

When we say that early N*'s were a common issue with this, we're referring to pre-2000 versions. In 2000 GM put longer studs in and reduced compression slightly to reduce cylinder pressures, relieving some stress on the studs some.

Before i even go any further, thanks for all the info...it's greatly appreciated.

What makes the 04/05 less prone, was it another stud revision? I also though I read they tried another revision in 2002 with no luck?

[CMNTMXR57]

Original (pre-2000) used M11 x 1.5 head bolts.
Revised (2000+) used M11 x 2 head bolts.

There is some discussion that the bolts were revised again, but simply thread pitch changes. Still a M11 x 2 though.

[Juggernaught]

I recently bought an '05 GXP with 32k miles on it. The engine looks to have been well maintained and pristine. It doesn't seem to have any coolant issues so far. However, I did change the coolant and trans fluid just so that I know when it was changed, and that it was done right. Next month, I'm having the brake and power steering fluid changed, so all the fluids will be "fresh".

If you haven't done so yet, I recommend you look in your spare tire well and make sure you have no trunk leaks. Even my low mileage car had some water standing in the spare tire well from a trunk leak. If you have the leak, there are threads on this site that will help you remediate it. Enjoy your Bonneville, I'm enjoying mine!

[PhoenixStar]

I recently bought an '05 GXP with 32k miles on it. The engine looks to have been well maintained and pristine. It doesn't seem to have any coolant issues so far. However, I did change the coolant and trans fluid just so that I know when it was changed, and that it was done right. Next month, I'm having the brake and power steering fluid changed, so all the fluids will be "fresh".

If you haven't done so yet, I recommend you look in your spare tire well and make sure you have no trunk leaks. Even my low mileage car had some water standing in the spare tire well from a trunk leak. If you have the leak, there are threads on this site that will help you remediate it. Enjoy your Bonneville, I'm enjoying mine!

I really love the car too, I've always been a Pontiac lover, and decided to go back a bit and get one last Pontiac as a daily driver before they get any older.

I read about the leak issues before I picked up the car, spare tire well and interior floors dry as a bone, no funny stagnant smells either.

I have to admit I am starting to panic (well maybe not panic) but am very concerned now about my fluid level. I had a low coolant temp light come on upon first start up in 28*F the 2nd day of ownership. I took a visual reading of the coolant level, seemed good, and the light went away, never came back and it's been 300 miles. CMNTMXR57 said it was likely the sensor, and i agreed. Upon purchase the salesman said oil was changed, and other fluids were changed as needed. I assume his mechanic topped off other fluids as well if needed, but I can't be positive. Anyways took a look at my reservoir today after I learned what the REAL cold level was from one of CMNTMXR57 's past posts, and I came to realize I was down 3/4 - 1 inch from that line cold. If the mechanic did indeed top it off, then I'm down an inch after 3 days/300miles, so I'm hoping he never actually topped it off. However, even at that level, my sensor didn't come back on. I topped it off to the cold line and will drive around some more to see if levels drop. After a 50 mile ride so far I cant smell any coolant under the hood, no obvious leaks, no white exhaust, runs like a champ, and the temp is perfectly fine while doing long 65/75 mph cruising. It was too cold to go back out and check the coolant level cold after that drive, I'll have to do that tomorrow. Fingers crossed.

[1oldman]

I have to admit I am starting to panic (well maybe not panic) but am very concerned now about my fluid level. I had a low coolant temp light come on upon first start up in 28*F the 2nd day of ownership. I took a visual reading of the coolant level, seemed good, and the light went away, never came back and it's been 300 miles.

I've never owned a N*, but the coolant "alarm" isn't reserved to just a N*. The '92 SSE we have had that issue about 15 years ago. It was the sensor. - BC

[CMNTMXR57]

I recently bought an '05 GXP with 32k miles on it. The engine looks to have been well maintained and pristine. It doesn't seem to have any coolant issues so far. However, I did change the coolant and trans fluid just so that I know when it was changed, and that it was done right. Next month, I'm having the brake and power steering fluid changed, so all the fluids will be "fresh".

If you haven't done so yet, I recommend you look in your spare tire well and make sure you have no trunk leaks. Even my low mileage car had some water standing in the spare tire well from a trunk leak. If you have the leak, there are threads on this site that will help you remediate it. Enjoy your Bonneville, I'm enjoying mine!

I really love the car too, I've always been a Pontiac lover, and decided to go back a bit and get one last Pontiac as a daily driver before they get any older.

I read about the leak issues before I picked up the car, spare tire well and interior floors dry as a bone, no funny stagnant smells either.

I have to admit I am starting to panic (well maybe not panic) but am very concerned now about my fluid level. I had a low coolant temp light come on upon first start up in 28*F the 2nd day of ownership. I took a visual reading of the coolant level, seemed good, and the light went away, never came back and it's been 300 miles. CMNTMXR57 said it was likely the sensor, and i agreed. Upon purchase the salesman said oil was changed, and other fluids were changed as needed. I assume his mechanic topped off other fluids as well if needed, but I can't be positive. Anyways took a look at my reservoir today after I learned what the REAL cold level was from one of CMNTMXR57 's past posts, and I came to realize I was down 3/4 - 1 inch from that line cold. If the mechanic did indeed top it off, then I'm down an inch after 3 days/300miles, so I'm hoping he never actually topped it off. However, even at that level, my sensor didn't come back on. I topped it off to the cold line and will drive around some more to see if levels drop. After a 50 mile ride so far I cant smell any coolant under the hood, no obvious leaks, no white exhaust, runs like a champ, and the temp is perfectly fine while doing long 65/75 mph cruising. It was too cold to go back out and check the coolant level cold after that drive, I'll have to do that tomorrow. Fingers crossed.

If I am reading this right, and the dealership is being truthful, and they DID replace all fluids, which would include a cooling system drain/purge/flush, upon refill, it can take awhile for the system itself to purge air and settle down to the proper level. Even following the proper GM procedure.

I seem to recall mine took at least a week of "topping off" every morning, after I drained mine down to seal the system (in a bunch of other posts around here as I had weeping freeze plugs).

Again, unless you're overheating (really, not just watching the needle and thinking that 210* is too hot), I'm talking in the red, you're leaking, or blowing white smoke out the back, or you have a nasty tangerine milkshake for coolant or a chocolate milkshake for oil, I still say it's purging/settling and if anything, it's just the sensor.