More cooling system questions UPDATE

[majicwrench]

Coolant is SUPPOSED to flow into the overflow tank as the engine heats up. A cap that doesn't seal will cause an excess of fluid in tank, but it sounds like your cap seals, thus the pressure in system.
Pressure is SUPPOSED to build up in system.

read back thru and I can't see what your problem is. What problem are you having?? If "hot" what makes you think so??
Obviously, it should not leak coolant anywhere. Get leaks fixed.

[georgeramos]

Good point Keith, I think Im struggling with confusion so it's hard to know how to be clear. here's what is going on recently.

Bought a new Fiat Rad cap, not aftermarket. Same time eliminated the leaky "tee" in the heater hose. Refilled the system burping it by raising the front and letting it run for 20-30 minutes with the cap off. i did see air bubbles at the rad. The next day car ran at normal operating temp, no problems.

The day AFTER that car ran hot. As I was driving on freeway Id say it climbed to 210ish. When i was stopped in traffic it seemed to climb a bit higher, say 225. I never sat idle long enough to see it go higher. When I got back on freeway it dipped to 210 again. Upon inspection the following day i noticed the overflow tank looked much more "full" than it had before.

I think what I dont understand is what actually happens when there is "air in the system" If I had to GUESS I would say my overflow tank is clogged at the base so pressurized liquid can push its way in but cannot escape. IF that's feasible would it then cause an "air in the system" event? Would that event cause the temperature readings i saw? is it actually overheating? Brad mentioned in one post that air bubbles caused false readings (Im paraphrasing how I read it, sorry If I misunderstood that Brad)

I hope some of this makes sense

[toplessexpat]

Is it possible that something kooky is going on with your heater controls - and there's actually a bunch of air in there somewhere??

A

[georgeramos]

Ive bypassed the heater core.

[toplessexpat]

Hmmmmm....

Is there some slow leak somewhere then? Have you tried filling up, cleaning off, and running the engine for 30 mins or so (through a bunch of cycles), with some sheets of white paper underneath the engine bay. I'm thinking not just drips to look for but spray / light misting of coolant. Revving and running at revs would "help" (albeit annoying to the neighbors / spouse). Also try holding some sheets at places within the engine bay.

A

[spider2081]

I believe the flow of water from the radiator neck small fitting to the overflow has to be unrestricted. Crud does settle at the bottom overflow bottle so I would think there could be something in the small hose. Actually the hose is the lowest point for something to settle.
I just replaced the radiator in my 81 with a repaired used one. Filled and burped as suggested. Took it for a ride temp went to about 225 before fan went on. I was an unhappy guy and thought the worst. parked the car for the night and the next morning I noticed the overflow bottle was down about one inch from where I had filled it the day before. I added coolant back to the Strap line and drove the car. It seems to have bleed itself as now all is good.

[majicwrench]

I really doubt it your overflow tank/line is plugged, but super easy to check.

225 is too hot. Is you fan kicking on?? Should come on 195 ish. Have heard no mention of fan operation.
When it gets to 200 is your radiator hot all over?? All hoses hot??

You keep talking about air in the system...what makes you think you have air in system??

[TX82FIAT]

I'm sorry you are having these cooling issues. It certaily can be frustrating and a good friend just sold his FIAT becasue he could not get it to run cool. In his case, he eventually blew the head... chicken or egg, did the head blow because it kept running hot or did he have coolant leaking in the head that lead to a blown head?

When car first starts up do you have any colored smoke out of the tail pipe? If coolant is staying in the overflow from a clog have you noticed any hoses look restricted/contracted. Is there room to add more coolant to the system indicating a possible leak? Is you fan kicking on? I agree with the driveway method of running through multiple heating clycle and checking temp of head, radiator, hoses.

Hang in there.

[georgeramos]

The fan switch was bypassed a while ago. I want to get the car running cooler before installing the new one and working on what might be faulty wiring. I wanted to rule that out. So it gets to 225 with the fan running. Im mentioning air because itsounds like a very common reason to experience this type of problem. I certainly dont know if thats my problem but when i saw how full the oveflow was i guessed if that much was displaced theres certainly room for air in the system now...

[bradartigue]

The rad cap is new. Could the head gasket be failing and NOT show oil in the coolant or vice versa? Is there any other reason that coolant would travel into the overflow?

Sure...pull out your plugs and see if there is green or crystalized crud on them; if so, you have a leak into the combustion chamber(s). Easy enough to diagnose.

Honestly I've never had cooling system problems on a FIAT (I'm not lucky, I just think the system is simple). So you have 1,000 ideas here and none are working, have you considered taking the radiator to a shop to be inspected, boiled, and possibly recored? That and replacing all of the hoses, the water pump and the thermostat and you've pretty much replaced the entire cooling system.

[majicwrench]

Bypassing the fan switch is often done cause coolant won't circulate. Again, is your radiator getting hot??

I hate the "let's change everything" approach. Wire your fan up properly, see if your radiator gets hot. If not, you have a circulation problem. Don't assume you have air in system just because it is a common problem?????

[georgeramos]

The rad was recored less than 2500 miles ago. Thermal switch and thermostat changed TWICE EACH. Water pump changed. Hoses except the thin overflow all new. I will empty the overflow bottle clean it out again and change that hose to see if it makes a diff. Seems things are overpressurizing because there have been systematic leaks or failures. Heater core, coolant tee. Both bypassed or eliminated. Now overflow bottle fills up after a day of driving. As i said things were normal that day indicating proper flows but next day ran hot hot and bottle appears much more full. Like 3 inches of liquid more full!

[4uall]

Sounds like the same type of problem I had when I first bought Fiona

have you checked inside (see link below)?

not trying to stir up another chase however, as mentioned previously you have tried everything else


http://wwwe.fiatspider.com/f08/viewtopi ... verheating

[georgeramos]

I have checked that Jay.

The cooling system has been pretty much completely rebuilt within 2500 miles and was working properly for much of that time. The recent rash of crap started when it ran hot and i noticed the fan running very erratically as if the electrical connection was spotty. I pulled the relatively new thermostat at that time and boiled it, it did not open. I ordered a new one as well as a new thermal switch. Installed the new stat but not the switch as i figured if i can get it to run at normal temps i could then circle back and deal with wiring and electrical then install the new switch. I understand keiths point about having the whole system running properly but i was thinking that the electrical fan circuit in and of itself has nothing to do with the temperature unless the fan is NOT running. If its running full time then the car should run cool right? I have no frustration with anyones replies btw. i appreciate them its just hard for me to relate how much work and time ive put into the cooling system and yes i agree brad it is a relatively simple syztem so why the hell cant i fix it properly. It was fixed entirely once and it worked. Now it is systematically failing anew not 2 years later. This is my frustration.

Back to the story. After replacing the stat and hard wiring the fan it ran fine. Until the heater core started leaking. Bypassed it. Then coolant tee started leaking. Got rid of it. Then ran hot again and overflow bottle filled up. A friend said his scorpion had a small head gasket leak and he had same issues. There is nothing else to replace but the overflow hose and the head gasket. Of course id rather not have to do the latter but i dont know what else to check. I got lazy and didnt do what i promised on saturday which was running water through all the places to check flows so i promise i will empty the system again and do that. Sorry brad. I know the system has been working so i thought that might be obvious but its not.

[4uall]

http://www.lovethispic.com/image/40636/ghost-hug