[andrejw]

i'm driving a '84 308GTSI(US version) and my problem is that the engine is running hot by stop and go traffic the temperature will rise till 240(airco off).
i've changed the thermostat en rebuild the waterpump also clean up the radiator en water pipes,the both fans are working fine but i've made a test bij overruling the thermoswitch so that the fans are running constantly
but there is no difference in temperature only when i'm driving on the freeway (80MPH) the temperature will lower at appr.200 which is normal
i think.
sometimes ther is so much pressure that coolant is coming out of the overflow tank i've also noticed that when the engine is warming up that the watermeter (when reaching 195) the needle is falling back at 170 but only once en for a short time.
does anyone know what is the problem
(excuse me for some wrong words but my Dutch is better then my English)

 

[Stradale]

Check you fans. There are 2 fans and they both have low speed and full speed operations and it may be that the full speed "coil" is burnt. This happened to me before the temperature goes high but gets back to normal when trvelling at speed on the highway. At idling the fans look like they're working but this is on the low speed coil. I had to change one of the fans. Perhaps you can get it re-wired.

 

[senna21]

Since you've done just about everything else you should also replace your radiator cap. It could be that it's no longer holding pressure. This would cause the car to run hot or over heat. Very inexpensive item but it has it's place in the chain and usually gets taken for granted.

 

[308ROB]

Running Hot

Hi, Andrejw. Welcom to the Ferrari Forum. We all do our best to give you the best information regarding your hot engine, so that soon your problem will be over.308ROB

 

[andrejw]

thank you for your tips en welcome Rob,
are you sure (stradale)that the fans has 2 speed I thougt this is only on the 360.
i go try first to replace the cap because this is the most inexpensive thing

 

[250lm]

Hi Andrew,

Can't help you with technical stuff, but did you happen to drive in Rijswijk last Friday? Saw a black GTSi on the Lindelaan!


Niels

 

[308ROB]

Hot Engine

Hi Andrejw, About the two speeds of the coolingfans, that is new to me and the first time to hear of it , but you never know it's Ferrari, infact I even try it on my own 308GTB but no results, so no two speeds of the fans.
There is a airbleed valve on your thermostatic-house, you have to bleed it
so that the air fully comes out your system. I'm sure you did this but anyway.
You overrulled the thermoswitch and it was ok'e, but you have to check if the fans are working when your engine is hot. The radiator cap opens on 0,9 kg. 308ROB

 

[4kids3fish]

You've checked all the easy ones. If the temp is still getting too high either :

1. the engine is putting out too much heat for the amount of coolant in the system, and/or
2. the coolant isn't being cooled well enough

On 1, could be
(i) insufficient coolant due to airlock still in system. I don't know the 308 procedure, but did you also bleed the heating system? It may be needed - try to find the factory coolant-refill procedure & follow it again.
(ii) combustion gases getting into water jacket due to head gasket leak (hopefully not!), which will also over-pressurise the system & blow coolant out.

On 2, could be
(i) fan problems (currently being checked), obstructed water passages in radiator / hoses / piping / block-heads
(ii) obstructed airflow to radiators or radiator matrix poor condition
(iii) insufficient water speed through system, due to airlock (as above).

The "warm-up" gauge-drop from 195-170 sounds like the thermostat opening (depending on where the gauge sensor is located). If the thermo opens quickly it can lead to a rapid mixing of the hot block water with the cold water sitting in the pipework & rad & can give a temporary drop in water temp back at the block for a few mins.

 

[andrejw]

both head gaskets are replaced 1 month ago because one was bad so i think this cannot be the problem but maybe you right about the obstruction, but i already have clean up the system,what is the best way to do this i have used Valvoline Radiator Cleaner?
I think your right about the dropping of the temperature that this is caused by the thermostat.
Is it possible that de radiator itselves could be the problem?

 

[andrejw]

Hoi Niels
I was not in Rijswijk because of the heating problem i can drive only on the highway and my 308 is Red

 

[4kids3fish]

The radiator should be able to be checked by a reputable radiator shop. They can also pressure-test the system for you if you are losing water.

The rad can probably be serviced by them (if new ones are too expensive or hard to find) by taking the header tank off (with brazing torch) and then "rodding-out" each of the small water tubes to make sure they are all clear of built-up deposits. The header tank is then rebrazed on & pressure-checked for leaks. If the general rad matrix is pretty tatty (many broken or corroded fins) then replacement is probably best.

Check the general condition of all the hoses too by squeezing them. They should be nice & firm & not spongy or with fine cracks when squeezed.

 

[wolftalk]

if the fans aren't turning on, then it sounds like air in the system is preventing flow. Eventually the water in the block boils out the coolant tank.

Assuming the thermostat doesn't have a small hole to allow flow all the time, then you get to burn your fingers a little while bleeding the system.

The basic procedure is to run the car until the thermostat opens, and make sure you have the heat on to get flow through those cores. Then open the bleed screw on the top of the radiator and let the air hiss out. Finally, open the bleed screw on top of the thermostat housing and let the air out there.

Usually you have to back the bleed screws out almost all the way, or remove them completely...that's how you burn yourself

As a test, you can run the engine and if you aren't getting heater output, then you aren't getting coolant flow.

 

[andrejw]

problem solved

thanks all off you for your replys. i've tried all the tips you send.
but there is one thing i did'n tried and that was measering
the temperature with a external thermometre in the overflowtank.
So i did that and compared with the watermetre next to the external metre and geuss what, there was a difference so to make sure i,ve buyed a new sender and tryd this again on a stoof at home. So i boiled some watre (195F)and with a external temperature metre(Fluke83 with TK80) next to the original metre there was still a difference.
I know now for sure that the metre was not correct and that the car does not run to hot the coolant which come out of the overflow whas because there was to much coolant in the system.
The solution for the metre is i put a resistor 68 OHM in serie with the thermoresistor (gray wire) on the back of the metre.
SO MY TIP, DON'T (always)TRUST YOUR METRES

 

[250lm]

Cool that you found the problem. Nice car you have there: I like the 328 add-ons (wheels and rear spoiller)!


Niels

 

[senna21]

That spoiler (just above the rear window and cooling vents) was a quatrovalve option. As were 16" wheels.

 

[4kids3fish]

Great work Professor Andrew!! :up:

 

[marcos]

Hi Andre,

Very nice 308 and I'm glad your problem was so small...