larryk

Need advice on overheating car, 91 coupe w/approx 200k miles. Started overheating about 4 mos ago. Changed thermostat, everything fine. Last week, started overheating again after driving maybe 12 miles in bumper to bumper traffic, decided to change radiator, still overheats (luckily only $120 to swap out) after about 10/15 miles. Mechanic suggested I try to change thermostat again since the water pump seems okay (doesn't make noise and doesnt show any visible leaking. Again, still overheated but only after sitting in traffic. Driving around casually and idling in the garage it will not overheat. This morning took out thermostat altogether and drove in bumper to bumper LA traffic for 1 1/2 hours and car did not overheat until I pulled into work and temp was all the way up. All plugs look fine (all equally clean). Is it my water pump and it works sometimes (like for the first 1 hour 28 minutes this morning??!!) , can it be a blown head gasket??!!

I really don't want to change the water pump if it's not broken yet. I have no clue what to check/how to check next.

Help!

Larry

 

bigdad

while it could be your water pump failing to ciculate enough water to cool, I would look at your cooling fans first. It almost sounds like they are not functioning.....as long as you have air flowing over the radiator you're ok, but when you are idling in traffic and the fans need to do the job of putting air over the radiator you aren't getting the cooling expected.
Fan controls and relays have been noted on this board as a fairly common failure....this is where I would look first....it could be something as simple as a sensor too.

larryk

Checked the fans, they both go on when they should be but the car will still overheat. It actually will start overheating sometimes when I am not in bumper to bumper traffic. It happens under different circumstances.

Can the water pump work sometimes and not work other times? I can idle the car in my garage for 30 minutes, the fans go on and off at regular intervals, and the car will not get hot!

tnelson

my overheating problem was the thermostat and water pump, in concert. did thermostat, stopped doing it as frequently, then did the water pump, which was leaking, and i was good.

peace
T

__________________
Real Life Trolling FTW....

http://www.youtube.com/watch?v=feLqz1udhtY

LPB

Are you absolutely sure the fans are functioning at spec? Do they remain on for about 15 min. when the vehicle is shut off when the vehicle registers as being overheated?

At 200k miles, the problem could easily be a bad water pump, especially if it is the original.
Hope the timing belt is not the original as it is way past its service limit. The water pump was supposed to have been replaced at 90k miles.

Did you install an OEM thermostat? Did you replace the radiator hoses? Check the timing.

BaByFaCeLeGeNd

I'm going through the same thing right, my cxar is overheating occasionally, sometimes its every other day, or every other time i drive... I had replaced the thermostat, and that wasn't the problem, so my mechanic had told me that it can either be a CO2 sensor in the engine or a bad guage, I'm thinking it might be my ECU because I had changed my ECU for the Bayou Stage II chip, any suggestions anyone??? I had my 90k service, so all belts, waterpumps, radiator is new, and I had 3 compression leak down tests so there were no signs of a blown HG... Also when its overheating when I'm idling soemtimes, the idle is weird because it seems to be idling fairly high so when I brake thorugh traffic it rumbles alot... HELP ME!!!!!!!!!!!!!!!

larryk

Changed the hoses, did not buy an oem therm. But right now i'm running NO therm and still overheated.

When a water pump on these cars goes bad, can it quit working only sometimes but be okay for a few miles? Does it always leak fluid when bad? Where can you see the fluid?

I know it's not a bad gauge as my reservoir is full (or overflowing if not shut down soon enough) after getting hot.

The engine will still overheat if running on a cool day going 40mph (at least once this weekend) so I don't think it's the fans not coming on/staying on. I would think that would be sufficient flow thru the radiator. As soon as I started seeing the temp rise I've turned on the AC to make sure the fans are on and the temp did not go down, just kept going up.

$174 for a pump at Autozone, $40 for a timing belt. Are these decent prices?

Hotstartup

get a compression test done!

LPB

A failed O2 sensor will set a code. Could you have placed a static charge into the ECU when you replaced the chip? If the problem surfaced immediately after chip replacement, you could have fried the ECU. Remove the Bayou chip and reinstall the OEM.

larryk

If it makes a difference, when it was overheating last night, I cranked up the heater and NO not air came out, only cool outside temp air. Is that an indication that the water pump is not circulating the hot water around (thru) the heat exchanger area?

Will do a compression check to see if everything equal in all chambers. If they are, then I guess I have no blown head gasket (no smoke now as it is)?

Hotstartup

sounds like blown HG! but just get a compression test and it shoudl tell you

FutureX 2001

I agree, blown HG.

Might as well do a Tbelt/Waterpump while ur at it. Actually since it's a 91 might want to go JDM engine, should be cheaper.

Don't want to jynx it, hope it's something else. Good luck. get a compression test done.

__________________

click

you are correct larry, that is a very good indication of if the water is circulating, if no heat comes out, the water isn't circulating through the heat exchanger and prolly isn't moving through the motor, sounds like ur water pump to me. but i'd start with the basics...kinked hose maybe...thermostat...etc. I don't know these cars that well...is the water pump turned by a belt off the crank? could be the belt slipping...that would explain the inconsistency...

stevieray

Blown HG. Same symptoms as mine. Cured with a new JDM engine for $2K. Good luck---

__________________


"King of Kleen"

"Know this. Being able to purchase a Legend and being able to afford a Legend are two separate things. Realize nothing post-purchase is cheap." - LegendGS

larryk

Not a blown head gasket. Compression checked out good. 180psi in all six cylinders. Had the dealer check it out. Either a cracked head or cracked block. Time to trade it in for a new car!