DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat banner

1 - 20 of 30 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
Hi all,

Running out of options. 2004/3.5L HO is overheating, but not when idling..it only approaches the high end of the temp gauge when you're driving over 60-70km/h for about 10 min. Running the heater at full blast or coasting at higher speeds is the only way to reduce the temperature when driving.

Mechanic's initial diagnosis was a blockage of some sort, so the rad was replaced to no avail. Mechanic replaced rad, thinking first was defective, but same result. Thermostat was replaced both times /w rad and is installed in the right direction. Latest tstat was checked using the "boiling water and thermometer" method and it opens at the specified temperature (180 F). Hoses all appear fine. If car is driven for until the gauge goes just over 1/2, the upper rad hose is hot, but the lower is only just warm.

No observable leaks. Engine oil shows no signs of coolant contamination. I've spoken to a couple of different mechanics and they keep suggesting there's compression escaping into the coolant.

So the questions I'm throwing out there:

1. Could it really be the head gasket, even if there's no coolant in my oil?
2. No one's ruled out the water pump, so how do I check if that's any good?
3. I've heard rumors of "anti-rust" compound coming loose in the engine and creating havoc with the internal coolant passages. Has anyone else heard of such a thing? Would a chemical flush remove it?

Appreciate any light anyone can shed on this. Love and still owe money on this car, so changing it for another is not really an option.
 

·
I hit **** with sticks!
Joined
·
37,341 Posts
Check the water pump for leaks for sure. It is behind the timing cover. If there is a leak there, it may only be leaking when the engine is hot, or very slowly, allowing it to evaporate before you see it on the ground. Check the fan operation as well. Radiator fans should be kicking on 215 degrees ish.

Have it block tested to check the head gasket for leaks.

A plugged cooling system should be obvious. Along with garbage seen floating in the system, if the lower hose is cold, and the upper hot, there is a flow problem (check this after the engine has been warmed up). This could be caused by a blockage, air in the system (caused by combustioin gas in the coolant, or air bubbles allowed in from a leak, such as the water pump).
 

·
Registered
Joined
·
10 Posts
Discussion Starter #7
Thanks. I'm definitely checking the water pump now. Is there anything else besides leaking and bearing wear that would be wrong with the pump?
 

·
Registered
Joined
·
13,180 Posts
Thanks. I'm definitely checking the water pump now. Is there anything else besides leaking and bearing wear that would be wrong with the pump?
That's about all that can go wrong with them, they are fairly simple.

BTW

There's a member in Whitby that pretty much all he does is work on these cars. If I were you, I'd go pay him a visit if you're not comfortable doing this yourself. He goes by the screen name TorontoFireCaptain.
 

·
I hit **** with sticks!
Joined
·
37,341 Posts
Thanks. I'm definitely checking the water pump now. Is there anything else besides leaking and bearing wear that would be wrong with the pump?
Thats about it. Since it has 125,000 miles, the timing belt and water pump should have been done at 100K. If not, get it done immediately, the timing belt could fail and cost you the engine! If it is all original, Ill bet anything youll find problems with the water pump.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #11
Yeah, I guess I'm living on borrowed time, since the pump and timing belt are the same ones that was on it when I bought it used at 25k.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #12
Timing belt and the water pump have been replaced, but same problem persists. Thanks for all the help and suggestions, though. Going to have system and block pressure tested. Also going to get coolant chemically tested for fuel mixture.

Not sure what else to do if that all checks out.
 

·
Registered
Joined
·
760 Posts
ill give you my 2.7L if you want,ill get that 3.5L off your hands:dead:
 

·
Registered
Joined
·
14,750 Posts
Are you certain the thermostat is installed in the proper direction? You have a new radiator, new water pump (hoses I assume) and the heater works. If the block check comes back negative (I hope so) this leads to the thermostat blocking coolant flow.

P.S. My '00 3.2L had the thermostat installed with the spring side inside the block, no overheating. I have never changed it.

Late!
 

·
Registered
Joined
·
10 Posts
Discussion Starter #18
"Are you certain the thermostat is installed in the proper direction? You have a new radiator, new water pump (hoses I assume) and the heater works. If the block check comes back negative (I hope so) this leads to the thermostat blocking coolant flow."



Yeah, it's got the spring and plug side inside the block. I sure hope the block test comes back negative, too. Thanks.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #20
Yeah, fans are coming low and then on high just shy of the 1/2 on the temp gauge. That's been the car's normal operating temp since I've had it. The fans do it some good at a standstill, but don't seem to keep up at normal city speeds.
 
1 - 20 of 30 Posts
Top