Technical My Barchetta is HOT!

[Kulgrinda]

Hi,

I have an issue with my car running too hot (please refer to the picture below). This reading I got driving in about +10 C on the highway at about 110-120 km/h. Temperature remained the same the whole 1.5 hour trip with both fans running at maximum speed almost all the time. Radiator was not very hot to the touch. Last time I drove it was 5 months ago, temperature would stay at about the quarter of the gauge.

There were some modifications made since last year. Cone air filter mounted, old heat shield removed and exhaust manifold wrapped with the special tape, straight through exhaust system mounted. Radiator was leaking, so it was taken out, sealed externally and refilled with new coolant+internal sealant. Thermostat is working fine, had it removed and tested.

My thoughts are:
1. Sealant has clogged an old radiatior.
2. Wrapping tape makes exhaust manifold too hot and lambda probes get wrong readings.
3. Air filter is sucking too hot air (that one could be withdrawn I guess, since I tried driving with partly popped hood, there was no change to the temperature, but filter was cold to the touch. Also performance remains the same. By the way - straight through intake and exhaust makes a huge difference in performance, cannot believe how agile and alive my car became )

So, has anyone faced any similar issues? Where should I start my investigation?

 

[Ilkka]

I doubt that the lambda would be so hot, that it would effect the measuring.
They can handle quite high temperatures, for example this Bosch lambda over 1000°C exhaust temperature:

https://www.google.com/url?sa=t&sou...gs3AQ_adGVrSJFpQg&sig2=KRJOzxYxck1D9FP3NkoKzA

I don't think it's the same type as the barchetta has, but just to give you an idea.

If the engine is running hot and you have checked all the above, then the radiator would be my primary suspect. You might want to check your water pump too, if replacing the radiator doesn't help.
Also, a damaged head gasket can cause overheating, but you would probably experience loss of coolant, bubbles in coolant reservoir or other symptoms if this would be the case.
So replace the radiator first - it's cheap and easy and if yours is original it's not a big loss of it turns out to be working.

EDIT: one way to test, if the overheating is due to insufficient cooling performance (ie. clogged radiator) is to put you heater to full blast when driving, and see if it makes a difference? It does have some cooling affect, especially compared to a clogged radiator.

 

[Kulgrinda]

Thank you for the explanation about lambda, I'll put this option aside.

As for turning the heater to max and blowing the heater fan - I did it while driving on the highway (remembered the situation we had high in the mountains). But I did not notice any significant change to the temperature. It reduced to about half of the gauge only when I entered city.

Barchetta radiators are difficult to come across in my country, also ordering one is quite pricey. Today I got some coolant flush liquid, two big plastic cans of distilled water and new coolant. Hopefully this will only be it.

 

[Ilkka]

pkwteile.de have quite a lot of barchetta parts.
http://www.pkwteile.de/autoteile/fiat-ersatzteile/barchetta-183/4760/10203/wasserkuhler-einzelteile
or ebay.de http://www.ebay.de/itm/KUHLER-MOTOR...chetta&hash=item21087870fb:g:o8AAAOSwYIhWlbTC
Cheapest ones are just above 100€ + shipping

 

[buchan barchetta]

Hi Kulgrinda, I could be wrong but it also seems like an air lock in your coolant systeme.

 

[Kulgrinda]

Thank you for advice! Yesterday I flushed system couple of times, rinsed with distilled water, filled with new coolant and sort of bled the system. There are some questions about the last part - I opened expansion tank cap, started the car, waited until it heated a bit and then tried opening the bleeding valve. I could not open it fully (as I could for example on my other car), bacause the expansion tank is higher that the radiator. Coolant just flows. So I kept the valve partly opened and waited for any bubbles, but there were none. Before filling new coolant I disconnected the top hose, and filled the radiator to the top. Then the rest went to the expansion tank. Is it the correct way?

I've seen a video where host would use a special funnel made to fit radiator thread. I was thinking of doing something similar with the bleeding valve, maybe it would work better?

Today I drove it for more than an hour in traffic jams, heat never exceeded half of the scale. But still I think it is a bit too hot.

 

[Ilkka]

Great to hear that helped! Halfway ie 90° is just what it's supposed to be.

 

[Davefridge]

Hi. I've had my B for 18 years and have changed coolant about every 4 - 5 years. never had any problem bleeding air out of the system. Just filled it up and run engine. Kept topping up until level in header tank stopped going down.

 

[itaa5x]

Had a problem with overheating just now as well, and the fault was that coolant was just leaking out all the time until I fixed the old busted coolant pipes.