I have a 91 Ranger with the 4.0 OHV. Since I bought it several months ago it's always lost coolant. I'm not sure where it's going. There is never a puddle under the truck and there is no coolant in the oil. I have also changed the radiator cap just to make sure that isn't causing it to evaporate. What should I check next?

Thanks in advance for your help

 

Well.. there are only two options left. Evaporation via a small leak somewhere that's not enough to drip/puddle. OR it's being burned in the engine. Blown headgasket, cracked head/block, ect..

First I'd pressure test the cooling system and look the radiator over for whitness stains of a leak. If you don't have a pressure guage/cap.. run it for a 1/2 hour driving and then park it in a quiet garage and carefully watch listen for a good 10 minutes.

Second I'd pull every single spark plug and look for any that are not the same colors as the rest. If you do find that.. you know it's being burned because of an internal leak.

Rich

 

start the truck and smell the exhaust coming out of the tail pipe.....if it smells sweet or is moist, then you probably have a blown head gasket....and that is were your coolant is going...

 

change the oil and see if there is any coolent floating in it.. if so its a head gasket, 4.0L OHV motors are known to blow head gaskets around 100k

 

How long does it take to loose collant? and how much coolant?

 

Good advice. And a compression test could be useful, as well.

Something to keep in mind too: a failed lower intake gasket can also lead to coolant sipping on the 4.0L OHV, particularly the earlier ones.

 

I pretty much lose coolant as soon as I put it in. I haven't kept good track, but it seems like it is around a quart a week or so. I'm going to fill it up tonight and check the exhaust as well as around the engine compartment. Any other suggestions would be appreciated as well.

Thanks for the help