three dodges in a row with this problem so i am cursed or dumb? this problem is a 95 3.9 v6. engine will overheat when driven above 45 mph. NO WATER IN OIL, oil is clean NO LOSS OF COOLANT, no drips and coolant stays full in radiator. Radiator foams, did I say FOAMS? when engine is revved. literally scoop a hand full. talking foam like a starbucks gone wild. not air bubbles. I flushed radiator with vinegar and distilled water. refilled with coolant and radiator water, cant get anywhere near what they say is capacity in this thing though. did a compression check and it is definitely back cylinder on pass side. (135 psi) next one up was 145 and front and all 3 driver side was 150.

This is the third dodge in a row for me to have this problem first was 89 318 (but it did use water and #3 plug was rusty looking) so it went to junk yard, next 96 v6 same problem (foam) clean oil and no loss of coolant just got rid of it. now here we go again. but three in a row has to mean dodge sucks or i am really doing something wrong. so while the compression tells me i have a problem and the temp gauge tells me i have a problem i dont know what my problem is and i need this van for my shop. any suggestions?

 

You still have air in the system. It' a bitch to get it all out......

Another possible: Worn impeller on the water pump, allowing it to cavitate, thus, putting bubbles into the fluid.

 

this isnt bubbles but real thick foam. it has a new water pump installed 4000 miles ago.

 

Ok, with the cooling system dead cold, and sealed up nicely, does it IMMEDIATELY build pressure when you start the engine? (hoses get rock hard right away...)

 

hoses never get rock hard. and if is squeeze them with the cap off i dont get as much surge as i thought i should. on a side note i did forget to install a thermostat when i replaced the water pump. so everything just flows all the time.

 

Ok, sounds like it ISN'T a headgasket problem then...... Not sure if not having a 'stat in there would cause the foaming..... but, it's possible. (flow turbulence, and such, ESPECIALLY if there is an air pocket in there somewhere.)

At greater than 40 mph, the condition of the fan becomes irrelevant, as there should be enough airflow thru the radiator to keep things cool. A blockage of airflow though might be something to look for. (crap accumulates between the condenser, and radiator, so, poor airflow.....)

I would also wonder about still having some air in there...... these guys are notoriously hard to get all the air out of the system.

 

i still have the compression problem on the back pass. side cylinder. but ignoring that for a minute. i believe the radiator slats to be clean. driving at night (much cooler) it seems the temp doesnt overheat. so i am getting good air flow. i think.

 

According to dodge.... anything over 100 PSI is 'acceptable'. So long as you don't have more than a 15 to 20% difference from the highest cylinder, to the lowest. (which seems excessive to me, but hey, that's just me.)

Still behaves like air in the system to me......

How's your cat? (converter.....)

 

i assume cat is fine. keep in mind i have had this problem across three motors. if it was an air pocket it wouldnt eventually work its way out? horrible fright has a radiator pressure test kit on sale for 64 dollars so i am on my way to buy one. i guess if there is air in the system this should find it?

 

No, the air pockets in these are stubborn, due to the way the heater core is plumbed, among other considerations..... pressure tester will only tell you if you have a leak, won't tell you if there is air in the system.