Hello everybody, I know the issue of overheating N* has been covered over and over again on this forum, but my particular issue(s) are a combination of everything. I have no idea where to start looking for advice because most of the issues that have been covered here look completely different than what's happening in my car.

First things first: low coolant warning. There is actually a bit more in the overflow tank than needed, but I'm planning to take it down to the stealership for a proper coolant flush. It's just that before I do that, there's some other things I need advice on.

The gauge constantly reads 89c, the middle is 90c and the needle is just before that (Canadian car, comes up to 192fahrenheit when converted, give or take.) which seems to be the optimal operating temp, except for these few things below which would indicate it is NOT working at optimal temperature at all.

The radiator hose is soft. And I mean soft-soft. I can pinch it. As far as I'm aware, it shouldn't be this way especially for a car with an engine this powerful.

While engaging in some spirited driving, I've noticed the car began to feel hot inside. The heating was off, but I felt some serious warmth at my legs and even the steering column and radio was hot to the touch. It was about 15c (59fahrenheit) outside and I had the window down, so absolutely no reason for that to happen.

Considering what I've managed to learn on this forum so far, it's possible that:
1. There's air in the coolant system. Hopefully this can be addressed with an authentic dealership coolant flush and replace.
2. The coolant temperature sensor needs replacement to address the "low engine coolant" warning
3. The thermostat needs replacing because if it's stuck in the closed position, the hose will remain soft because no coolant is being circulated.
4. Bad water pump.

I have a couple of budget code readers but they're coming up empty. Literally not a single code is being given. The cluster panel intermittently gives me "service stability system" warnings but I think I can ignore that. I drive with traction control off anyway. Besides that it's the once in a while "low engine coolant", outside of these 2 things literally nothing else, and no indication of anything happening either outside of the above described symptoms.

Hopefully I can get someone with a tech2 at the dealership to maybe get more information on what's going on with this car when I go in for the coolant flush. Maybe while the coolant is out, they can replace the thermostat and the engine coolant sensor if that will make things work better. The reason why I'm posting this is that yes, I can get most of my questions answered at the dealership, but the appointment is in a few days and I still need the car before that. I don't want to destroy the Bonneville or blow myself up so I need to know how serious these issues are.

The low coolant warning is from a failed sensor built into the reservoir, unfortunately you have to replace the entire reservoir. It is nothing to do with the temp sensor.

Since your coolant temp is remaining steady and the head gaskets are holding coolant, I don't think you really have a problem.

If your thermostat was stuck closed, the car would be overheating.
If the water pump was bad, the car would be overheating.

The service stability system is from a faulty Steering Wheel Position Sensor located at the base of the column

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 55k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 95k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 260k | Official Bonneville Hauler

Hi,

Thank god it's not the worst what I expected to hear, but I must ask: what's with the soft radiator hose? I mean it's the same density whether the car's on or off, that can't be good, right? It's supposed to be under some pressure at least. The coolant reservoir hissed and shot out a little bit of coolant when I didn't give it time to cool down properly.. And what's with the heat issue in the car's cabin? For reference I didn't redline it or push the speedometer that hard.

And 2nd, the stability system warning is really the steering column sensor? I thought it was that sensor in the wheel hub itself. Do you know if it's possible to do this at home? And with limited tools? I'd hate the airbag to launch me through the ceiling.

Edit: it seems the reservoir was replaced already, it's a Dorman replacement unit. I want to get the original GM one but it doesn't look like it comes with a sensor or even a cap. Should I just get the Dorman again or..

This might help with your steering wheel position sensor issue:

suspension-steering/topic18539.html

I just did mine (again) yesterday.

_________________

Resident Tightwad

Screw you, Photobucket.

This is an amazing resource! Thank you. But.. I've got bigger problems now, I'm afraid. I went to the dealership for the coolant flush and transmission fluid, and what I discovered is absolutely awful. The car leaked coolant all over the service bay floor, even though I've never saw it do that before. However after I got home, I saw there was a stain on my driveway which I didn't notice because the driveway was recently sealed so it must've been leaking for a while now.

Anyway, after an inspection and a pressure test, they definitely saw a leak. They didn't really pinpoint the location of the leak but they narrowed it down to possibly coming from the water pump housing, which has been discontinued. It's not that bad because I can probably source and rebuild the water pump assembly with the gaskets if I look hard enough for about 1.5k give or take, but what I thought was initially 251k km engine actually turned out to be 251k mi engine. The car was American but I guess the previous owner just inserted Canadian gauges. The reason was after looking at the odometer it didn't match what the tech2 brought up, which said the actual odometer value was over 400k km. All in all I was told that there's absolutely no point in trying to fix it, which is a hard pill to swallow considering everything, and I was told that if I really like the car that much the better option would be to get a new engine entirely. I have absolutely no idea what I'm going to do now. I was motivated to invest my time and money into bettering this car but when the GM techs who have worked on these cars for years and can obtain any part it needs tell you that you're screwed..

I feel absolutely awful and this new information really took all the enthusiasm I had for this car right out of me. Before I was so motivated to turn this into a showroom-worthy street beast but all I've got now is a lemon that's hoarding valuable driveway real estate, leaking random fluids down the asphalt.

You guys have been cool, and for how small the gxp community is you guys really know your stuff and have even managed to create some sort of a support network, but I really don't think any of this applies to a car when it's in this bad of a condition. Seasoned professionals have no idea what's wrong but they're all telling me to avoid throwing money at it.