98 rodeo coolant leaking

[FL 3.2L]

A gallon every other week?

[duke36]

Im thinking its more than that...I have to drive 10minutes to and from work every day. If I fill the reservoir up its empty in about two days.

[amigo-2k]

Maybe there is a crack in the reservoir?

it is pretty easy to pull out and check.

[pharm_rodeo]

Originally Posted by duke36

Im thinking its more than that...I have to drive 10minutes to and from work every day. If I fill the reservoir up its empty in about two days.

Hard to believe you're losing that much and not seeing it somewhere.

[Ramblin Fever]

If you're losing THAT much, I'd say the engine is consuming it, even if the oil is clean.

Unless you do have a bad radiator, but even then, you should be able to see *something* green on the frame underneith.

Same thing occured on my late Toyota, coolant kept running away, never could find it anywhere obvious, oil was clean too....til we opened up the engine cause it refused to finally start. Whole entire bottom-end was swimming

[duke36]

still havent found the leak to this day....no coolant in coil packs so im guessing a blown head gasket maybe..can anyone think of anything else before i take it to the ol dealership for a high price diagnostic?

[Florsuzo]

If you aren't seeing any leaks then the engine must be consuming it.

Are you in a place where steam comes out the tailpipe every morning?

Try a pressure test when the engine is cold. Most likely you have a pinhole or tiny crack in the head near the exhaust valve and when the engine is warming up it's burning off the coolant and pushing it out the tailpipe. Once operating temperature is reached thermal expansion causes the crack or hole to close and no more leak (which may be why the pressure test passes). The head near the exhaust valve runs a bit more hot natually due to the exhaust passing through the port.

A crack in the head would keep your oil clean (whereas if the head gasket blows it typically blows between the combustion chamber and the oil/coolant galleys which is why you get milky oil).

Any bubbles in the radiator when the engine is cold and you start it up?

[amigo-2k]

I still think I would dump in some stop leak in the rad to see if it fixed it.

[duke36]

when i top the radiator off with the engine cold there are bubbles that pop up and the fluid goes down but I thought that was just the coolant settling...then I add more coolant

[duke36]

Have you used some and it worked without messing any other components up...I havent heard of anyone using that stuff and it worked...

[Florsuzo]

Bubbles in the coolant at the neck of the radiator = compression leak into the cooling system.

For what it's worth the leak sealers claim to work on internal components but I have never had it work. Do you want to take the risk of thinking the problem is patched and then have the plug blow loose leaving you stranded?

Sounds like you have a cracked head. Being that you have two heads I would run a compression test and check the spark plugs. Chances are one of the cylinders will come up lower and/or one of the plugs might be discolored compared to the others.

[duke36]

okay guys help me out here...I had a friend at work pressurize my cooling system. With the oil cap on the system passed the pressure test. With the cap off the pressure slowly began to fall. He said that it wasnt a crack head or blown head gasket cause if were either of the two the pressure would have fell regardless if the oil cap was off or not. He diagnosis was a leaking intake manifold gasket. Something about water jackets running thru the manifold which i didnt think it did. Help

[Ramblin Fever]

Leaking intake manifold gasket is VERY common on the 2nd generation Rodeo's...so it's a big possibility.

[Florsuzo]

A leaking intake manifold gasket won't send bubbles streaming into the cooling system.

If you fill up the coolant and start the engine when cold does the overflow reservoir's level rise? Does your exhaust have a sweet smell to it and does the steam linger? Normal exhaust will dissipate quickly when the weather is cold; burning ethylene glycol produces white dense steam that is rather like fog. A spark plug with whitish or brownish deposits on it could indicate the bad cylinder head.

[duke36]

Does anybody know where i can find a diagram of a 98 isuzu rodeo DOHC to find freeze plugs. And also, are they even possible to change out if I locate them?