03 Montero Overheated, Dripping Coolant, cause?
 

3.8L 6G75 Engine.


I drove it home on a cold night and sat in my driveway a few minutes listening to tunes. I looked down and the temp was high (250F if I remember right). I drove it in the garage and shut it off. There were no visible signs of steaming, smoke, anything.


Next day I took the skid plate and under engine plastic pieces off to see if I could see anything. It looked like coolant fluid dripping down passenger side of the block, not a lot.


I checked fluids and it was low on Oil AND Coolant. I filled radiator up, and added a quart of oil back in. (I did need more than a quart but thats all I had at the time). I drove it easy around the neighborhood, monitoring temp and engine characteristics. Everything seemed normal to me. Idles fine, power seems normal. Engine came up to temp and t-stat seemed to work. Engine temp remained around 190 during driving.


When I got back it still looked like there was fluid dripping down the block from some place that I could not see. I opened the radiator and it was missing a bit of fluid (obviously leaking somewhere). Water hoses are fine.



I think that the overheat was just due to low fluids...but, cause of this being?

• Oil - typical blow by over time
• Oil - some slow leaks from exhaust manifolds looks like
• Coolant - water pump? Replaced 4 months ago when timing belt was done. Perhaps timing belt is too tight and impeller eventually tweaked?

Would the head gasket start leaking like this?
What else could cause this?


Oil is dark but not milky. Exhaust does not blow white.


I want to avoid paying for a head gasket job...my plan was to continue looking at engine for obvious sign of leak. Unfortunately I cannot see the water pump without tearing quite a few things out...headers do look "wet" on passenger side.


Are there some tests I can run, or places I can look?

You can pressure test the cooling system to see if there is a pinhole leak somewhere that allows coolant to seep out.
Test the head gasket for leaks - there are kits out there to check if you have a blown gasket. They are not 100% accurate, but they should work in most cases if you have an issue.
As far as timing belt being too tight - did you properly tensioned the timing belt idler pulley? If so - the belt tension should be within spec. If not, no one can say if its too tight or too loose.