Head Gasket?? (1 Viewer)

[Firsttimer]

Hi, so I've got a question. My 85 BJ70 is having some issues. So, I have no problems driving the thing around the city. But, last week I took a 2 hour journey to my home town and after about 1.5 hours on the road the Cruiser started overheating. I looked under the hood and the overflow for the rad fluid had filled up and was spewing coolant all over the road. Luckily I had some water with me, so I just put in as much as I had and nursed it the rest of the way home. I filled it up at home, adding about a gallon and a half of coolant. After the weekend, I drove it back to where I live. The exact same thing happened after about 1.5 hours.

Thinking my head gasket was going, I re-filled the coolant and took a look at it while the engine was running. I cannot see any bubbling at all. I believe the thermostat is working as, when I drive it around the city, I can see it kicking in - i.e. the temp. starts going up, then all-of-a-sudden it drops (when the thermostat kicks in). I've been driving it around the city for about a week since the problem first started, but it has not done it again.

Any ideas as to what is happening?

I was thinking I might take the thermostat out and then go for a drive. If the temperature goes up despite the thermostat being out, then I probably have a blown head gasket -- you guys have any other ideas??

Thanks!

 

[Radd Cruisers]

Location?

~John

 

[Firsttimer]

Saskatoon, Saskatchewan

 

[Radd Cruisers]

Temp rising and then a sudden drop suggest that perhaps your thermostat is not operating properly. They can hang up a little when they get old and not open smoothly or progressively.

The single most common issue with cooling systems (other than just an outright lack of maintenance) is an old rad cap.

The next most common issue is a partially plugged rad from lack of service, too weak a coolant mix, or using non-distilled water (deposits block the passages).

The whole cooling system needs to work as a system or you will have real problems. If the rad is blocked or the thermostat is not working properly, then the fan won't engage when it should since it requires hot air flowing past it to do so. If the cap is leaking, then you won't get the system up to pressure, no pressure means the boiling point is too low and the coolant will blow out of the rad prematurely...

It all has to work together to get the job done. I'd suggest starting with the basics - rad cap, thermostat, hoses - and then move on from there.


~John

 

[kbushnz]

As suggested, sounds like a sticky thermostat. I had one hang up in my around town car. When I replaced it there was a lip worn on one side.
Changed it, and never done it again.

 

[Firsttimer]

Thank you both very much!