2003 Tahoe coolant system leak or head gasket leak?

[iamdub]

100 miles later all is well. When I come to a stop, the idle is so smooth, first few times I thought the engine stopped!

Question for you all. That buzzing from the sensors on the ceiling, how do you disconnect them or delete them?

Also what could I add to my rear end oil to reduce the chances of having to have to replace gears later than sooner? I have a slightly whine when on the gas. Stops when I let off the gas.

As Tony said, you can try cleaning it. Or, replace it. It's only about $25. I'm not sure, but just unplugging it might cause faults in your HVAC system. If you go through the trouble to access it to unplug it, you might as well just replace it.

I replaced mine about six months ago: https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/post-1615656

As for the rear end, have you ever replaced the oil? If not, drain, clean and refill. I'm partial to Mobil1 Synthetic Gear Lubricant LS. It has the additives for GM's limited slip diffs and (IIRC) is perfectly fine in non-LSD-equipped models.

 

[tomloans]

As Tony said, you can try cleaning it. Or, replace it. It's only about $25. I'm not sure, but just unplugging it might cause faults in your HVAC system. If you go through the trouble to access it to unplug it, you might as well just replace it.

I replaced mine about six months ago: https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/post-1615656

As for the rear end, have you ever replaced the oil? If not, drain, clean and refill. I'm partial to Mobil1 Synthetic Gear Lubricant LS. It has the additives for GM's limited slip diffs and (IIRC) is perfectly fine in non-LSD-equipped models.

Yes I have replaced the oil three times since I owned it. Not really bad yet. Yes in regards to the sensors. I will just get news ones and take it on one day.

I am getting the smell of coolant from the car now. Definitely not losing it like I use to. But still there is a smell. I was hoping it might be residual burning off somewhere. Will drive it some more and see if I lose coolant.

 

[tomloans]

Just hit that sensor with some compressed air, just some dust clogging it up.

I will try this now. Thanks!

 

[iamdub]

Yes I have replaced the oil three times since I owned it. Not really bad yet. Yes in regards to the sensors. I will just get news ones and take it in one day.

The sensors are easy to replace- maybe an hour or so job. Well, at least the one above the driver's position. Never messed with the rear one.

I am getting a the smell of coolant from the car now. Definitely not losing it like I use to. But still there is a smell. I was hoping it might be residual burning off somewhere. Will drive it some more and see if I lose coolant.

Check at the ends of ALL hoses (at firewall, radiator, etc.) and gasketed joints (like where water pump meets the block) for any chalkiness or dried crud. It could be a simple ill-placed or loose hose clamp. Check the radiator end tanks- you might've had one on the verge of cracking. Or maybe you just didn't tighten the cap on the surge tank. lol

 

[tomloans]

The sensors are easy to replace- maybe an hour or so job. Well, at least the one above the driver's position. Never messed with the rear one.




Check at the ends of ALL hoses (at firewall, radiator, etc.) and gasketed joints (like where water pump meets the block) for any chalkiness or dried crud. It could be a simple ill-placed or loose hose clamp. Check the radiator end tanks- you might've had one on the verge of cracking. Or maybe you just didn't tighten the cap on the surge tank. lol

Well I replaced the water pump about 40k miles ago and literally everything (I mean everything) else in the cooling system about 5k ago. I put pressure on the tank and couldn't find the leak. But unlike last time, I am not losing coolant like crazy. I am going to drive it some more and see what happens. Who knows it may puddled up somewhere and is slowly burning off.

 

[Tonyrodz]

Well I replaced the water pump about 40k miles ago and literally everything (I mean everything) else in the cooling system about 5k ago. I put pressure on the tank and couldn't find the leak. But unlike last time, I am not losing coolant like crazy. I am going to drive it some more and see what happens. Who knows it may puddled up somewhere and is slowly burning off.

How are the plastic tees on the firewall?

 

[iamdub]

Well I replaced the water pump about 40k miles ago and literally everything (I mean everything) else in the cooling system about 5k ago. I put pressure on the tank and couldn't find the leak. But unlike last time, I am not losing coolant like crazy. I am going to drive it some more and see what happens. Who knows it may puddled up somewhere and is slowly burning off.

AC Delco OE water pump?

 

[tomloans]

How are the plastic tees on the firewall?

Yes I have brand new GM ones attached. Put some serious pressure on the expansion tank and usually they will start dripping and no drip. Everything is tight and double checked. I am leaning towards the Water Pump. But we will see. It is a very small leak and I am sure it will start to get larger so I see where it is coming from.

 

[tomloans]

AC Delco OE water pump?

Can't remember, trying to figure out where I bought it.

 

[tomloans]

Water pump was back 5 years ago and 50k miles ago already. Crazy how quickly time flies by. Don't have any record of where I bought it. Hmmm. I think I am going to watch it for awhile see if the pin hole grows. It is a quick and easy job so no big deal. Compared to what I just did, it is nothing. Thanks again guys. I will check in from time to time.