1999 Chrysler Concorde overheating / failed emissions

Help,

I have my mother's 1999 Chrysler Concorde LXi 3.2 V6 engine with automatic transmission. She overheated and did not have the money to have it fixed, so I grabbed it Christmas and tried to do the repairs myself since I knew we were looking at thousands of dollars.

We did not see any water in the oil so I don't "think" she blew a head gasket, but the radiator was cracked, so we replaced the radiator and no overheating for a week or so, then it came back. It appeared when stopped or driving slow. That lead us to the thermostat. Replaced that and it ran another week or so without issue. Then it wouldn't start and we diagnosed and found some fuses and a relay that were bad because it sat at my mother's for about 3 months idle. Then, the air bag light came on. Read up and replaced the clockspring. I was real proud of myself at this point and it ran fine until now.

It overheated again AND this time the heater is blowing cold air and I failed my emissions test due to O2 sensor "NOT READY". I don't know if one thing has to do with the other as I'm a junior novice mechanic. It seems like we lost coolant somewhere, so I added more. I don't see it on the ground anywhere, but I do smell it inside a little but don't know if that's just because we added more. It seemed like the heater got a little warm while driving but immediately went cold when I stopped. So, stomped and don't know where to go from here other than back to the dealership which I've been trying to avoid.

1. Will the dealership diagnose a leak if I pay their $80 fee or will they charge more to do that? I'm scared that they might say yes you have a leak but it is $100 more dollars to do a pressure test and find the leak. I don't know how to do that myself.

2. Is there a good way to tell if I have a heater core problem and would that lead to overheating and cold air blowing? I don't know if the core could leak so much coolant which would cause overheating.

3. Is an O2 sensor related to any of this and is this something that may be a problem since the car has sat so long? Autozone said that they can hook it to a machine that would tell me for free, so I hope that pans out. I have NO idea where these sensors are OR how to change them. They look like they just plug in somewhere and it looks like there are more than one of them.

Any advice would be much appreciated.

Thanks,
KeithGP

 

Welcome to the Forums!

Sorry to hear about your situation.

A bad heater core will cause overheating, but usually not a off and on type of thing. The heater core will leak into the passengers side floor board area, or the engine firewall side.

You have checked all your hoses? Sometimes a hose will leak and the dripping will get burned up on the exhaust manifold.

Your water pump may be going south also.

There are many things that could be wrong. I would do a complete coolant flush if not done so already.

It may also be a blown head gasket or cracked head if you are now getting bad O2 errors.

The dealer will charge you the fee to diagnose. They should find the problem.

You can check for a blown head gasket or cracked head by doing a compression check. You can get a compression test kit from Autozone (rent). You basically pull the fuse to the fuel pump, remove one spark plug, insert pressure guage, and crank. Do this on all spark plugs. PSI should be within tolerance from cylinder to cylinder.

Also, have you observed whether or not your radiator fan is turning on?

 

Time out fellas........"Overheated when stopped or driving slow"??????...Has anyone checked the coolant fans???? Common problem in those vehicles .......and there's an updated relay to fire them off too.........I'd sneak a peek in that direction ................and then do a block test to check for a blown gasket..........Does anyone SEE any coolant leaking friom this puppy????

 

wrench: read the last line in my post. ^ :-p

 

Thank you guys a ton. Yup, the radiator fans are working. There has to be a leak somewhere but I don't know how to find it, so I'll take that in and hope they don't charge me a fortune to find it. I'm sorry to hear that the O2 sensor may mean head gasket.

I'll see if Autozone can help with a compression test.

At least I have somewhere to start now.

Thanks,
KeithGP