91 4.0 overheating, cooling boiling over

[bjohn]

Ok, I'm going to start at the beginning. About 15 months ago I bought my 91 Ranger with a 4.0 and about 150k miles. Ran great, drove great. After having it for a while I started to notice that it would lose coolant, about a gallon every 2 weeks. It didn't put any on the ground, and there wasn't any in the oil, but it would just disappear. I replaced the radiator cap thinking that it may have been evaporating, but that didn't work. So I just kept driving it and adding coolant as necessary, after all I only paid $1300 for it.

Well, the other day I was driving to work and noticed that my temp gauge was increasing rapidly toward 'H'. I pulled over and put some coolant in the reservoir, then started it back up. Well, after running for a few minutes it vomited all of the coolant I put in it plus more out of the reservoir. I got the truck towed home and here it sits. I'm thinking this could be a bad head gasket, intake gasket or cracked head. Anyway you guys could help me figure this out? Would it be worth it to put new heads on the vehicle or should I look for a new truck?

Thanks in advance for the help

 

[fordnut71]

do a compprestion test to see what you have for cyl psi.

 

[little x]

It's a bad head gasket, or cracked heads. Do the compression test first, maybe you only have to pull off one side. But, if it was losing that much fluid, it's probably both sides. I think it's worth it for new heads (I put new ones in mine). These are good engines, as long as they don't over heat and crack the heads. . .

 

[marragtop]

Sounds like a Head gasket, but I suspect that was bad all along. You may also have a stuck Tstat at this point. You might get away with just replacing the Tstat and continuing to add water periodically, rather that pulling the heads.

 

[Skotty]

Out of the blue my T-stat froze shut.The needle was resting comfortable in the red zone.15$ later i was back in buisness.I would check the thermostat first.Also what does your coolant look like.IE oil in the mix?