I don't know if this where to post ..sorry but I searched everywhere.

Suddenly my new (used) car has begun to overheat. After a freeway drive and stop and go through the city (San Francisco), came to a light and saw boil over, turned on heater fullblast (does heat) and gently drove home 1 mile. Parked overnight, next morning gave empty fill tank, water, I had no coolant, went 2 miles to Kragen bought coolant, and put in a cup. (Oh the gauge never rose until it was steaming over.) It's always just below half..

I then drove 2 miles and stopped and it started boiling over again,big time. I went home. in idle the next day I checked to see if the fan ever comes on... it didn't, so I swapped a relay and then it started to function, and no more boiling over. Problem solved????

Feeling that i had the solution I drove 15 miles cross city and freeway, once again no gauge warning and it started boiling again... while in line waiting for gas. I topped it off, although the radiator itself was not too low, just the fill tank. The car engine doesn't even feel that hot. Both hoses, lower and upper are the same feel, and I can hear the fan works. and in when at an idle. Went to a Honda dealer and bought another new relay several miles from the boil over. It wasn't hot at all then. When I drove home back through SF, made several stops, looked for spills, Not... drove home over the hills,pulled into park and the gauge shot up and boil over. Now I'm wondering and quite concerned....Is this too dangerous to drive at all now?

The history is that it blew the 1 head gasket last march when my best friend owned it. He put major $$ into it at his Honda Dealer. It has 185 K on it and really until now has had not even a hickup. One thing he told me is that it never overheated during the 12 years he had it from new. I'm wondering if the gauge is not telling the true story. Also do you know what next i should look for?

Sorry for the long story, but I thought you should know as much as possible. 1998 Ex V6 3.0 Vtec engine, Coupe.
Bev----rolling

 

When car is fully warmed, and you stop the engine, the coolant in the engine gets very hot from residual heat soaking the coolant. Hondas (at least earlier models) had a feature for the cooling fans to come on w/ keyswitch Off for 15 minutes to prevent overheating. This is bad for the head gasket and reason for this feature.

Lack of fans running when engine is shutdown could result from a faulty thermoswitch B (on upper radiator hose fitting at engine side on earlier models), damaged connector, or wiring. Try shorting the connector to thermoswitch B, and see if fans come on w/ keyswitch off.

A failed thermoswitch B could have contributed to the first headgasket failure you mentioned.

good luck

 

Thanks TexasHonda

I know where that is but i guess i don't understand what "shorting the connector" means..

The fan does come on now, since i replaced the relay and while idleing after a trip like yesterday about 3o miles with several stops. I'll check once the after stopping mode. I don't think it lasts 15 mins though. At this point though should I even risk driving it because it will take quite a whirl around the city before it heats up enough for the fan to come on. Should I just leave it in park and let it idle for awhile?

Bev rolling

 

"Shorting the connector" means placing a wire jumper across the pins of the electrical connector to thermoswitch B. Fans should immediately come on w/ keyswitch in Off position.

Look carefully for bubbles in the coolant reservoir and a gasoline smell to the coolant. Both of these are indicators of head gasket leaking exhaust gas into coolant. There is also a chemical test that can be performed to confirm exhaust gases in the coolant.

good luck

 

Hi Tex
i checked for a gas smell.. none. Saw no water on dip stick. I saw that the coolant tank threads are warped and ran the car awhile around the area, heard the fan come on often, the gauge never went up, and when I pulled in to park I was overflowing out of the coolant tank. I checked the radiator and it got low so with the engine running I put just water in. I ordered a new coolant tank.

Apparently my friend said that shouldn't make a difference... now I find out. I'm taking it to my mechanic tomorrow to diagnose. He'll pull the plugs to check also, run a pressure test on the radiator, and we'll see what happens I'm afraid to drive it but I have no choice because I can afford him. Am I crazy? I will baby it all the way and turn on the heater full if needed.... stop and water it.... just like a horse.

Bev rolling

 

Coolant overflow can be caused by a faulty radiator cap (relief opens too low pressure).

good luck

 

Hi Tex
Hope you don't mind the nickname... I ordered a cap, and t-stat to take with me. I'm prayin, as I have to cross 2 bridges to see the guy who works on the car. I trust your judgement though, and somehow believe it's a simple solution. Do you believe I need the new coolant tank? The threads are warped so the cap leaks or rather blows in this case.

 

No, the coolant reservoir cap is not a pressure seal, just a "splash" shield.

good luck

 

Tex
It was the radiator cap! All the components of it had fallen apart and were laying in the neck! Since this is so new to me I didn't ever open it.... used to have an Audi that had no R cap. I pulled little piece by piece out, but one little rubber groment slipped away and I couldn't get it out. Do you think it will do any damage? Once again ty for all of your help, and everyone else who weighed in.

rolling

 

You might try draining the radiator, disconnecting upper and lower radiator hoses at radiator and rigging up to flush w/ garden hose from bottom to top. This might push the part out of the radiator inlet on top of radiator. I'm not sure the part could get past radiator cooling passages and down to bottom of radiator where coolant leaves radiator to return to engine. It may be trapped in the top of the radiator. If it stays there (seems likley) it may not hurt anything.

If part gets into engine, it could stick almost anywhere. Only place it might do harm is 1) water pump causing damage to pump or 2) thermostat, partially blocking flow.

Glad problem solve, but sorry about the part. Hopefully all will be OK.

good luck