Overheating!?!?!?!?

[verycoldfiat]

can't seem to win on this one. i've gone through bleeding the air out of the system about a thousand times,can't find any blockages anywhere, but the overheating continues,any help would be great. i'm about to drive the car out of the snow belt and down to LA.so thoughts and advice are more than welcome

[courtenay]

Does the fan come on?

[ORFORD2004]

Why don't you test the sensor in hot water to check your gauge?

[So Cal Mark]

alot more info would be helpful. Does it overheat at both idle and while driving? Does it get to the red zone on the gauge? Does the fan cycle on? Does the water circulate in the radiator once the t-stat opens?

[narfire]

After I recently swapped heads, it took quite awhile to bleed the system of air. Before bleeding the temp was over 190 and no fan, getting concerned I parked the car on some ramps I made on our sloping driveway. Let the car run for 5 minutes or more and air was continually comming out of the open rad cap(as well as coolant). When it finally stopped I topped it up,noticed the fluid moving and then the fan kicked in. Job done. Others do it simply with the coolant "T" on the heater hose but I just hav'nt got around to that yet. Is your thermostat on the right way? Air lock at the thermostat, check IAP service bulletins, I think they show where to drill a small hole in the thermostat so air won't get backed up.
Good luck with the drive... brave soul this time of year.
Chris

[verycoldfiat]

so....little more info. i have the "t" valve on the upper rad hose, it will overheat idle or running. just replaced the thermostat last season. have checked the sensor in boiling water and confirmed it's working properly.it just seems that it's not circulating in the rad no matter what i do. i just recently replaced the heater core.the only thing i haven't tried is replacing the thermostat again,just in case i have a faulty one.aside from that the fan does kick in......but it seems irregular,and last yep it makes it right up to 260 on the dash gauge if i don't have the heater control open, and even then i suspect after a little time it will get there again with it closed,but i'm not willing to wait for that.

[courtenay]

Sure sounds like air in the system to me. Have you made sure your heater is turned on when you bleed the system? Can you feel the rad hose below the T stat? If it's cooler than the hose above the t stat, then either the t stat isn't opening or there's an airlock in the line. If this is the case, the bottom of the radiator will also be cooler than the top. The temp sensor for the fan is at the bottom of the rad.

[azruss]

once it gets to temp where the stadt should open, feel the lower radiator hose. if that hose is staying cool, then your thermostadt isnt opening. the fan takes its reading off the bottom of the radiator, so it wont turn on if its cold.

[verycoldfiat]

thanks everyone. gonna try the thermostat and go through the whole thing this weekend while i replace the transmission......i guess the next one is to find out if i've damaged the rad or anything else with all the pressure in it. yikes.time for a little attention, after all we had to get it out of 3 feet of snow to get it in the garage.nice. but worth every minute!

[majicwrench]

"T" fitting should be in heater hose, not upper radiator hose.

[divace73]

It might be wise to have your radiator overhauled while you have your hoses off. The T piece in the heater hose is the way to go as it is the highest point. I do the following
1. Ensure heater in on
2. ensure a small hole in the thermostat as sugested
3. Obtain a T piece and put it inline with the heater hose that runs from the back of the head to the heater core ensuring it is the highest point.
3. Fill up coolant in the radiator till just above the top outlet.
4. Disconnect the top hose from the radiator turn it 90 deg up and pour in the collant until is come back out the radiator (this may take a while)
5. Connect up the top hose back to the radiator and top up from the radiator till full and there are no bubbles coming out, gently squeeze the bottom hose to see the coolant rias and fall in the neck without bubbles, then put the cap on.
6. Then open the heater hose T piece and loosen a the Front 'bleeder' bolt a couple of threads from the front T union (above the coolant temp sensor). Pour coolant in the HIGHEST POINT heater hose T piece until it come out the bleeder bolt. Tighten the bleeder bolt and then top up the heater hose t piece.
Tightend everything up start the motor and should it all have gone well the the needle should be somewhere in the middle or below and should the fan cycle twice after some time the job is complete.

Hope this helps

[Zippy]

Do you know the condition of your radiator? If it is restricted that could be the problem. I was plagued with overheating in my pick up for a long time until I finally broke down and replaced the radiator. Since then, absolutely no problems.

[verycoldfiat]

that's my last ditch effort....the one thing i noticed tonight when tuning it up and checking a few things was a small leak in the top seam......wondering if this is where my air pocket is starting????????....in which case anyone know where to get a decent priced rad, or anyone have any luck re-coreing them?

[divace73]

the small leak from my faulty cap has caused me the same grief just this past Sunday.
I drove down the the Fiat Nationals which is a 1.5 hr drive from Sydney and she ran beautifully untill we pulled over for a coffee break and noticed a small drip, continued on then about 10 min from my destination she started to over heat, got there justin time.
Before arriving home I filled up using my highest point method and made it back home with no drama, was doing 110 klm all the way. My cap does seem to seal one way better that the other?
I'm hopng to pick up my new cap this arvo.