Recently bought my 2nd 97 12v. Currently has a long warmup cycle 20 miles + and was going to replace the thermostat (with a big block per Michaels suggestion) Turns out I have a small amount of oil in my coolant :sad4:. both the thermostat and oil cooler have formagasket and the heater core was recently replaced. I am suspecting that the oil cooler was recently checked or replaced and perhaps the form in place gasket is not so good. Question is what year make and model thermostat do you suggest? Secondly does the oil cooler break down and leak with age like the heater core? I do not seem to have coolant in the oil and am hoping it's a problem that replacing the gaskets on the oil cooler will fix. Hopefully not a blown HG. Any suggestions welcome.ThanksRich

Remove the oil cooler, cap the oil passages so you can apply air pressure to the oil and dip it in a bucket of water to look for air bubbles.If you are working in freezing weather a couple of gallons of windshield washer fluid is a lot cheaper for washing the oil out of the cooling system without the hard water problem from cold weather. Dishwashing detergent and lemon juice work well for getting the oil, oxolic acid will get all the rust.Check all the hoses inside at least one end for oil damage.I think yours has 2 square o-rings for a thermostate gasket, mine has 1, the RTV may have gotten where it should not be.I have been running a Stant thermostate, below 40F it will give a couple of swings on the temp guage. One of my friends had continual swing that was cured with a $50 Cummins part that has a plastic sleeve in the middle.If you do not know the age of the hoses, it may be well to replace them with the antifreeze.

Be aware the only reason for a heater core, oil cooler or radiator leakage is from lack of coolant changes. Dodge recommends that you change every 30K miles. Now from a few posts I've been informed that the oil coolers are a dealer only item and costing upwards of about $600 bucks... :shocked:

Wow! Thanks for all of the info! Cleaning out the oil was to be my next question, thanks. I'm sure it would be wise to pressure test the transmission cooler (on the coolant side) after getting this all corrected as well. Will do on the coolant changes, I am holding hope that once I get it off the truck I will see signs indicating oil bleeding past a hastily installed RTV seal.

Be aware the only reason for a heater core, oil cooler or radiator leakage is from lack of coolant changes. Dodge recommends that you change every 30K miles. Now from a few posts I've been informed that the oil coolers are a dealer only item and costing upwards of about $600 bucks... :shocked:

Not exactly..........What kills more radiators and heater cores is the use of the wrong water. Distilled is prefered but RO water is the best. Tap water or well water ect has too many minerals, iron, sodium, ect ect in it which can causes corrosive conditions along with abrassives and also causes caking and plugging of cores. Mixing of different coolant recipes/brands can be a bad deal as well.

Yes, also dissimilar metal corrosion by the minerals accumulating in the bottom of the slowest moving and coolest areas? I once witnessed the large aluminum fuel tank of a boat that was ruined by a penny that someone had dropped into it several years prior. It made a perfectly clean penny sized divot (with engravings visible) in the bottom of the tank. It sure would be nice if there was block drains like the older V8's used to have. Again, several good cooling system guidelines. Periodic thorough flushing with thermostat temporarily removed Completely drain flush fluid Refill with 50/50 mix of distilled water and appropriate coolant only

Not exactly..........What kills more radiators and heater cores is the use of the wrong water. Distilled is prefered but RO water is the best. Tap water or well water ect has too many minerals, iron, sodium, ect ect in it which can causes corrosive conditions along with abrassives and also causes caking and plugging of cores. Mixing of different coolant recipes/brands can be a bad deal as well.

Funny... I've been using tap water so far for the life of the truck and not even had a bit of rust or anything at 5 years and 100K some odd miles... Even took pics... I'm on well water but normally load with irragation water (creek water)... Crazy maybe... But Zero build up, Zero failure yet...

Eh, I wouldn't be advertising that too much lol. There are a lot of people who have bad water, with sulphur and other crap in them that may cause a lot of buildup. So even though the creek may be fine and dandy, I wouldn't suggest this for everyone.

You do have a point there... :bang:

But still even with good water (distilled and coolant) and you leave the coolant in too long you will end up with the same problem in time... But I've been changing every 30K miles...

Here is mine at 100K miles and 5 years...

Edited January 13, 201015 yr by Mopar1973Man

Hmm, the inside of mine could rival the coral reef I change it a lot but of course there was 250k on it when I got it and it looked the same way. Is there anything I can dump in and let sit and eat away all that crap after draining everything out and disconnecting it all from the engine?

I would contact a radiator shop and ask them what they use to clean out a block and radiator... Like I said I've used nothing more that standard Prestone and creek water to flush my system. I'm coming do for my next flush I'll grab pics again... I'm sure its going t o look fine again...

Also copper is a lot more forgiving than aluminum rads and cores. Alum will get the "Corral Reef":p lol... thing going long before copper will too.