1990 1.5L, could a blown head gasket cause coolant to blow out of radiator when cap is off? Car was over heating so I replaced the thermostat. Now ,when car is running it pumps all the coolant into the overflow bottle. If radiator cap is off it blows like it's under lots of pressure. Any ideas? Dan

 

it IS under a lot of pressure.

Chances are, your radiator cap is bad.

 

hmmm head gasket isn't likely to be the cause... what i'd do is flush the system out... and make sure it is actually flowing through the engine and go from there... if its not flushing out right well you have a clog...

 

you blew a head gasket. your cylinder that is blown is pressurizing the cooling system and it has to go somewhere E.G. out the radiator cap. Stop driving it and fix it.

 

Head gasket - with the engine COLD take off the radiator cap and fill the radiator up. Leave the cap off and start the car. If the engine runs like crud then rev the engine - if water JETS out all over the place then it is 100% the head gasket.

- There are other problems and symptoms that a head gasket can give you, but I have had that one happen before.

Now, if the old faithful action happens when the engine is HOT and not when it's COLD, then there is a clog in the cooling system. I had a thermostat stick shut and that is exactly what happened.

 

The original headgaskets on those were junk. Honda has an updated headgasket and bolts. They have a service bullitin on it.

 

Thanks everyone, apparently my sons ex-girlfriend overheated it three times before she brought it over. We found coolant in three cylinders. Head is severly warped because of bad thermostat and driving while overheated. Thanks again, Dan

 

Gasket blown into 3 cylinders. Checked head and block for flatness, checks OK. Installed new head gasket and it's running like new.

 

You lucky on that, but congrats.

Good luck with the engine.