97 3.8L series 2 vin k OVERHEATING

**mlheands** · 07-05-2010

We had an overheating issue. We changed the thermostat to see if that would solve the problem no such luck. We found that the intake manifold was leaking so we changed that(the piece on top with the plastic). Refilled the antifreeze(regular). Still having a problem. Checked the thermostat again it was stuck closed. So put in new thermostat again. Looked like it was going to hold temp but after the engine warmed up it started overheating again. Realized maybe antifreeze issue, drained and flushed. Put in DexCool but still overheating. Water pump is circulating the fluid no indication that it is bad. We also replaced the radiator with a new one. Seems to be burning antifreeze in exhaust(white smoke upon first startup but none after engine warm). Holds temp around 200*F for about the first mile or 10 minutes til engine gets warm. Just at a loss as to what else could be causing the overheating issue. Oil doesn't appear to have antifreeze in it nor is it cloudy or milky either. How would I tell if antifreeze in oil? If there is what would cause that. I have the new plugs but have not changed them yet. I know it is misfiring on one of them. My low coolant light comes on and service engine soon light came on when the intake manifold started leaking. Any advice or suggestions would be greatly appreciated at this point. Thank you

**Bio248** · 07-05-2010

your lower intake manifold gaskets are probably gone. you should have done that when you replaced the upper manifold.

**mlheands** · 07-05-2010

Ok checked oil and there appears to be antifreeze in the oil...Any suggestions?

**Reptile** · 07-05-2010

As Bio has said, you need to change the lower manifold gaskets before it gets any worse. They are the ones that go between the head, and the piece under the plastic intake that you changed.

**mlheands** · 07-06-2010

Well, we checked the 2 bypass pipes and apparently the vehicle leaked at this location prior to us having it. Instead of spending the $18 to fix it they put silicone on the ends and put o-rings that didn't fit...We replaced them and the engine is running about 220-230*F not superhot but still hot...When you shut engine off you can hear the antifreeze boiling especially in the hose connected to the thermostat....radiator cap not getting as hot though....We think the water pump may be weak and not working properly seems to work ok when idling but once you start giving it gas and the engine warms up doesn't seem like it is pumping enough to the engine....So tomorrow starts another day....If the water pump does not fix the overheating issue is it safe to say it's the lower intake or the head? I just don't want to have to pull everything all apart again....Pray it's just the water pump...I'll let ya'll know what the outcome is after the water pump is changed....Thanks for all the help so far and thank you for this forum without this I would have not known about the two bypass pipes that go bad on these

**Bio248** · 07-06-2010

if coolant is going into the oil its a 99% chance that you'd need to change the LIM gaskets.

**The Guz** · 07-06-2010

Like Bio said. Replace the LIM gasket before you experience any other issues.

**TheOtherNick** · 07-06-2010

Its simple put the intake gaskets in it or put an engine in it in a few weeks from spun bearings.

**Ibwrong** · 07-06-2010

Change the LIM gasket and get the aluminum gaskets from the 04+

**mlheands** · 07-07-2010

Ok, after thinking about this and realizing that you guys probably know more about this situation than I do...I am going to replace the LIM and while I'm there I'm changing the water pump since I already have it...Sorry for being stubborn but just needed that swift kick to wake me up and realize "Hey they obviously have dealt with this before and I should shut up and LISTEN." Thanks for the swift kick....I will let you know the outcome.

**matt5112** · 07-07-2010

water pump isn't really near the LIM.

**The Guz** · 07-07-2010

Originally Posted by matt5112

water pump isn't really near the LIM.

True but it's pretty accessible when doing the LIM.

**mlheands** · 07-11-2010

Ok, now I'm at a loss...we've put new lower intake, head gaskets, valve covers, water pump....but still running hot....fans are working, new radiator, new thermostat, new upper and lower thermostat bypass pipes, new upper intake(plenum?), new plugs....could it be the coolant temperature sensor? Any suggestions...PLEASE....Thanks