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94 Concorde 3.5 L over-heating problem. Zoomed to top of scale very fast.

I had been night driving about 30 minutes when I looked down and noticed the temp gauge had red-lined all the way to the top, without me even noticing it. It couldn't have been more than two minutes till it had topped out. Then the check engine light came on. I was driving in an area where I didn't want to stop so I kept on for the next mile or so until I got the car into the driveway, when it shut itself down, with a terrible rattly sound.

This is a rural area so I consider myself lucky to have gotten it home.

I opened the hood and noticed steam, though not sure exactly where from. As it was late, I just left the car to sit overnight. Next day I checked the oil (down about 3/4 quart, seemed typical) and 'low/no' coolant in the reservoir. I started it just to see if it would turn over, which it did just fine. I topped the oil off and added as much water as the reservoir could take..about 6-7 quarts went in..it takes

12 quarts total).

It started fine, ran up to regular temp at idle and per the hose heat test, the thermostat seemed to be working ok. I have brought it up to running temp twice since then (about 20 minutes, once driving, once idling) and it seems to be running normal as could be. No engine noise at all.

My question is what might have made it spike like that and would the next thing be to replace the thermostat/gasket?

Could it have been a sensor of some sort?

The car has seen very limited local use throughout its life, but has been driven moreso during the past year. Its just hit 40,000.

Thanks

Brian

Reply to
usethisone2007
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its possible your water pump impeller is loose on the shaft. has it ever been replaced? its turned by the timing belt. if its never been done, i bet your car is due for both to be changed.

Reply to
rob

Low on coolant.

I'd find the coolant leak first.

If it's leaking coolant.

Reply to
aarcuda69062

My first guess would be the same as aarcuda's. You ran low on coolant. Keep an eye on the temp gauge and the water level. If the water level drops find out where it is going.. Leaky hose, leaky water pump, leaky radiator.

Steve B.

Reply to
Steve B.

Believe it or not, my wife even had a 3.5 water pump seize up, but the timing belt continued sliding on the WP pulley without even making any screeching sounds. Took a bit of diagnosis to figure out why it was overheating for no apparent reason, until I caught a whiff of burning rubber smell coming from the timing case cover. When I got it apart, the back side of the timing belt was badly glazed from the friction and the belt was obviously not reusable, but it wasn't shredded. I wouldn't have thought it possible.

Reply to
Steve

yeah mine was doing that as well at the end. heard a nasty noise coming from it. dead giveaway.

Reply to
rob

Thanks for responding.

I was wondering about how thermostats typically 'go out' though.

Is it all at once or do they just not work all the time? I will probably put a new one in as its a very cheap part and easy to do, but I won't really feel too confident about driving it without knowing the old one was the issue.

I will do the boil test on it I suppose.

Regarding the loss of coolant. Could that have been cause by the boil over/steam I witnessed when I opened the hood? The temp gauge hasn't read hot until that one, and so far only, time.

Brian

usethis> I had been night driving about 30 minutes when I looked down and

Reply to
usethisone2007

yes

When was the coolant last checked before the incident happened?

Reply to
aarcuda69062

When you said yes, which were you saying yes to?

It probably hadn't been checked for a couple months.

I've since driven it quite a bit more, probably a good 30 minutes freeway speed, then a 30 minute cool off time, then back 30 minutes. The needle functioned perfectly, no overheating.

I can't be sure how much coolant was in there when the incident happened.

I bought the thermostat as it was only $7, but I'm now thinking about not putting it in yet...because it may have just been low on coolant......and it somehow went off. Someone looked at the engine and claimed it was so clean he didn't suspect any burst hoses or leaks.

Brian

Reply to
usethisone2007

Both.

That's a poor maintenance practice. You'd have a much better direction to go if you checked it regularly and knew that it was full just X days ago.

The O-ring that seals the water pump to the right side timing belt cover and the identical o-ring that seals the timing cover to the engine block were a known failure point, as were water pumps themselves up until (IIRC) 1997 when they and the timing belt were superceded with the late model items. I find it hard to believe that a failed thermostat caused the 50%+ coolant loss unless you totally didn't see the warning gauges/indicators and kept driving and driving, in which case, I hope more drastic damage didn't occur.

Reply to
aarcuda69062

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