Hello. I have a 91 that started leaking coolant recently. The only area I can see it puddling up is right below the thermostat housing and where the water pump pulley is. It eventually runs down to where the RMS is. I have not driven the Jeep in a couple weeks and takes a while to start again after cleaning it off. I do not see anything coming from the hoses and seem to be tight/dry.

There is also some pressure in the cooling system, when I take the radiator cap off to check it wants to spill out some.

Any ideas? Nothing seems to drop straight down from the water pump area.

Brett

 

When it's cold, spray the whole area with WD40 then blow it off with air. Use a cooling system pressure tester and pump it up to system pressure and watch it closely. The WD40 will make it bead up so you can see the leak better. You should be able to "rent" a tester at a parts store. Most of the tool rentals work where you buy it, then get your money back if it's returned undamaged. Inspect the tool before you pay for it to make sure it IS undamaged. I own one because I rented one without checking it and found the cap tester adapter was missing when I got home. After using it, they wouldn't take it back because that part was missing. I guess I was their sucker!

I got thinking! (Wow, what a concept!) You said radiator cap, right? Doesn't your 91 have a pressurized remote reservoir or has it been converted to the open system? Either way, WD40 will show the leak because the coolant will bead up as it comes out. You may just have to wait until the engine heats up to see it. They tell me a Volvo cap fits that reservoir.

 

91 first year of open system......