So--- my wife brings our 90 model montero home the other day saying it was running a little hot. So I checked and it was low on coolant. Filled it up and started it and it starts steaming ot of the exhaust. I pull it in the garage and hook up an air line into each cylinder and pressurized each one individually. Saw no bubbles coming out of the radiator. Could this be a problem with an intake manifold leak or ?? Any help would be great.

Welcome to the club! Your not a full member until you had one cracked head or blown head gasket. <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/frown.gif" alt="" />

Yup, sounds like one of those. If you're an optimist, it's the HG.

Head gasket. "Little hot" translates to thermonuclear overheat. The little darlings will NOT pull it over to the side of the road when it gets hot, so the head warps and the gasket seal blows. My wife was one of the "little darlings". It is not politically expedient to bring this up, however. Just bite the bullet and fix it....

Note that compression pressure alone is probably above the regualtor limit on your air compressor, not to mention the much higher combustion pressure on top of that. A more reliable test is one for combustion products in the coolant. Lisle makes a kit for this (p/# 75100, I think) for about $50, available at parts stores. You will probably also see coolant loss in the rad/overflow.

I paid $400 for a complete rebuild on my heads, and another $450 for a head gasket set, all new water hoses, new water pump, all new belts, and all new acc. and timing belt idler pulleys. I did the labor. 3 hours of teardown, 2 hours of block deck cleaning and gasket scraping (and that's NOT excessive), and 6 hours of put back.

All this has got me really confused now. I built this motor about 2.5 years ago and not one problem until now. Anthor stange thing is that I pulled the upper manifold off and it had coolant coming from it. Maybe the water jacket in the throttle body?

Maybe, or water flowing into the intake thru an open intake vavle. The manifold is wet at the carb base, and has two water passages thru the flange, so leak cound be carb base or manifold/head gasket or cracked head or blown head gasket. If it overheated, I still say head gasket.

Did you build the cooling system also? Radiator rodded, new fan clutch, water pump?

Here you go, mechanic-in-a-can. <img src="/forums/images/graemlins/lol.gif" alt="" />
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