1998 Isuzu Rodeo Question overheating

Hi there,

Thank you for the donation,

I feel that you may have a blocked radiator, have it cleaned and flow tested, (just doing a back flush won't do) it will need to be leaned by a radiator specialist, start here.

Mark (mhpautos)

Hi there,

make sure that the pressure cap is breaking off at the correct pressure, this is basically the safety valve for the system, a new cap will not cot much to make sure that its ok, also I would be doing a Co check of the cooling system, this will detect and exhaust gasses in the system.

Mark

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Mark

Your description of bubbling in the coolant jug, using coolant and oil burning sounds like you have a bad head gasket at least. That could also cause the number 3 misfire. There are a few checks you can do but one of the easiest would be to remove the spark plugs from a couple cylinders and cylinder 3. If the miss is being caused by coolant the plugs from the other cylinders will be dirty and look used while the one from cylinder 3 will look very clean.

This shows a few of the tests you can do to verify if it is the head gasket:
https://www.2carpros.com/articles/head-gasket-blown-test

If you have the 3.2 engine it's easier to replace the head gaskets with the engine out of the vehicle and while it's out you can replace any parts that have been cooked by the overheating which would likely be most of the seals and hoses, Or drop a remanufactured engine into it if the rest of the vehicle is in good shape. It would depend on the mileage, condition and overall "health" of the rest of the vehicle as to which option would be better or less expensive, however the 3.2 isn't a good engine to overheat as they tend to warp the cylinder heads easily.
I would start with the testing and then decide from there. If it's a situation where you just want to run it until it gives up you might try something like Blue Devil in the coolant. I've seen it seal small leaks in cooling systems and head gaskets but it's been sort of hit or miss.