97 towed home!

[lwalling]

I just had the 97 I bought last month towed home after it started to
overheat severely (and VERY fast).

Prior to the overheating the car was not providing a considerable amount
of boost - in fact it sounded like the bulk of the boost was being vented completely. Shortly there after, I started to hear a
rattling sound and the exhaust note changed dramatically and then the
car started to overheat (very fast) and I stopped the car rather than
trying to finish the trip home. It took 3 hours to get it home, trying
to find someone to tow it.

Upon inspecting the underside of the car no coolant leak was found, the coolant was blowing out of the overflow line. No contaminants were found in the engine oil.

Does this sound like catalytic converters or an exhaust blockage in general? The PO replaced them 5k miles ago ! How would be the best way to test the theory that that could be the problem - just disconnect the exhaust and see what happens ?

Thanks for your help in advance.

[danny tattersall]

Sorry to hear about your troubles. Sounds like you caught it before any serious damage such as head gasket blowing / head warping though if that is any consolation. I think your problem could be a variety of things but it certainly would not do any harm to remove the exhaust and look down the catalytic converter to ensure that it is not loose and causing a restriction (possible reason for rattle).

Did the car slow down dramatically as your problem developed or was it just a case of the boost pressure being low? A blocked cat would result in both of these happening;the harder you press down on the accelerator the harder the loose article is jammed. Also, the temperature would rise due to the extra work done by the engine to maintain speed.

Good luck. hopefully other people will contribute and help to resolve your problem (seems like many of them are more interested in carbon fibre bits etc than helping solve people' s technical problems)

Danny '93 SE.

[rlearp]

The situation you describe is similar to one I encountered on a early 80s Mustang that "melted, for lack of better word" its' cat. The car started to overheat, power dropped off dramatically, and there was some nasty rattling from the exhaust pipe which was bits of the cat. Almost exactly what you describe, so, I hope that is it.

Remove the exhaust, simple to do, and check it out. One of the reasons my Esprit has no cat, just something else to go wrong!

R

[MikeyRide]

lwalling said:

Upon inspecting the underside of the car no coolant leak was found, the coolant was blowing out of the overflow line. No contaminants were found in the engine oil.

Is coolant blowing out of the overflow line because it overheated or does coolant blow out and THEN it overheats? It's very possible (has happened to me) for a blown head gasket to vent pressure into the cooling system w/o getting anything into the oil.

[lotusman]

I had two instances of such a problem. They both centered around the thermostat of the car. My Honda and Ford both started overheating. The coolant overflow bottles filled up and overflowed. In one case the thermostat bulb had broken and the increased pressure it should have expanded with to open was not there. In the other case the thermostat had got into a bind in its housing and would not open. Replaced, no problem.

If the cat is plugged, how would it start at all. Did you not see, "Beverly Hills Cop"?

When was the last time the coolant was changed and the system flushed?

I also found in my Lotus recently that a large piece of rust existed in the header tank that could close off the pump suction hole. I had a new all aluminum header tank built and installed.

But please let us all know whenever you get the problem solved.

Lotusman
'89 non-SE

[lwalling]

Just pulled the cats.

The car starts and seems to run OK with them disconnected, and there is no coolant being pushed out of the reservoir (ie positive pressure from a blown head gasket, etc).

The turbo impellers freewheel by "finger", smooth as can be.

Going to try to get a look inside the cats, have to hunt up a flashlight! .

Any other advice while I'm under there ?

[lwalling]

I refilled the coolant, hooked the cats back up and pulled the muffler, and let the car run with all the accessories on. Never overheated. In fact not even a hint of it.

The boost problem is still there, how does one troubleshoot a wastegate for failure ? The arm is movable and the valve opens and seems to close properly. I don't know exactly what I'm looking at though.

How can the overheating problem be explained? There is no leak. No coolant in the oil. No pressure pushing coolant out of the system.

[lwalling]

How much resistance should there be, roughly, to pressing the waste gate arm forward on the turbo charger with the diaphragms connected?

The passenger side moves pretty smoothly and can be pressed with moderate force. The drivers side is smooth but VERY hard by comparison - nice indentation on my finger from pressing it open.

I don't have the proper tools to check this out but the fact that there was a difference in the motion tells me one or the other is probably bad ?

Thanks.

[dr.hess]

I am no expert in this area (turbos), but in general (and this is something we use in medicine all the time), if you have two of something that are about the same, like hands, legs, kidneys, turbos, etc. and they are significantly different, then you likely have found a problem.

Dr.Hess