Faulty radiator cap?

My '82 308 has begun to make sporadic noise when fully warmed up. I warmed it today to check the oil level (from what I have read, the car should be run for 10 minutes to fully warm up, then the level checked as soon as it is shut off- please correct me if I am wrong as the level seems extremely low even after adding oil, although the pressure did come up to nearly the mid-range after adding oil). When the engine was fully warmed up the car started to spew coolant from the overflow container, and made a growling noise a couple of times, which I attributed to the cap popping open and closed. I have had no problem with overheating- the temp always warms only to the mid-range. After cooling, the level in the overflow container is extremely low (at most 1/2" in the bottom). Would anyone think that this could be anything more than a faulty rad cap? Is there anything special on an F-car rad cap (I assume not)?

 

When I had overheating issues, the first thing the mechanic did was replace the cap. Of course it ended up being the radiator, but from I am told, check the cap first...it's the cheapest way out.

 

a worn out cap spring is VERY common.

buy a 1.1 bar

 

It could be the cap, or it could be air in the system. A bad cap over time leads to air in the system, so do not assume that because it has not overheated, that you do not have air in the system. I would replace the cap, and then properly bleed the system. Complete instructions here:

http://www.birdmanferrari.com/coolant/coolant_bleed.htm

 

I have not had much luck finding a replacement rad cap, and want to get the cap replaced and bleed the rad prior to taking it out. O'Rielly could not find a suitable replacement, as they could not cross-reference it, and NAPA near us has closed. Does anyone know where I can find a suitable cap, and what the store's stock number is?

 

I had the same problem; it was the cap and the cap alone. Changed the cap and problem was gone.

 

On my '79, I use a Stant cap (p/n 10229). There is mention of a p/n 11229 in the 308/328 Parts Cross-reference thread, as well. EVERYbody should have Stant caps in-stock - best of luck!

 

This is the cap that I tried, but O'Reilly does not carry Stant, and does not have a cross reference for them. I will give AutoZone a try and hope for the best.

 

Check with some of the Ferrari parts suppliers like Ricambi America, Dennis McCann, T Rutlands, I'm sure they would have one.

 

Make a mental "note to self" not to go back to O'Reilly - EVER - as they sound worthless!

 

While replacing the cap had a positive effect, I think that I will need to bleed the radiator as the problem was not entirely resolved. A new problem popped up, though, that I hope someone can help with. The last few times out the temperature gauge sits low, then suddenly swings to near max (~110), sits there, and after a couple of minutes suddenly drops back to normal. This repeats itself every couple of minutes. To me this sounds like a thermostat needing to be replaced. Does this sound right, or does anyone think otherwise? Could it simply be air in the lines messing with the thermostat?

 

No downside to ensuring that your cooling system is properly bled (and it's not hard to do) -- do that first, then, if you still have weirdness, dig deeper.

 

That was kind of my thought- bleed, drive, and if the problem persists I will look into it further. Assuming bleeding does not resolve the problem, does it sound like thermostat to you? Would that not be the next thing to check? And based on the parts reference, I would be looking for:

THERMOSTATS ( NOT CORRECT OEM)
VW GOLF / RABBIT 1980 REF
VW PN# 056121113A 180F
VW PN#05612111371 160F

 

Rick, you suppose to wait 15 min after shutting the engine off to check oil level.
And preferably drive it instead of letting it idle for 10 min.

 

I have heard varying opinions on checking the oil, even from Ferrari mechanics. The last mechanic (specializing in Ferrari) says to run the car just long enough to fill the filter, shut off, and immediately check the oil. There is no real consensus that I can find.

 

RAM,

Today I just had the same problem with my overflow as you described. What radiator cap did you end up buying? Store, brand and part number.

Thanks in advance.

 

Obviously you need to eliminate the Tstat and coolant level issues, if any. But head gaskets blown to the water jacket produce all the symptoms you are describing with temp fluctuations and water being ejected from the coolant tank and the subsequent water level being low. Coolant can be checked to determine if there are exhaust gasses present. This would be a good thing to do and is easier/cheaper than performing a leakdown test which can also identify this.

 

I went to AutoZone, as they have a cross-reference for the Stant 11229. I am not positive off hand what their part number is, but the cross-reference is in their computer.

 

Those are thermo-switches which activate the radiator fans. Very different than a thermostat which is near the water pump. Are your fans properly turning on and off, and together? Sometimes one will die. Other times the thermo-switch can fail, and the fans never come on.

 

I had thought of the fans, but could not see them correcting cooling that quickly. Am I wrong?