Hello All, Before I posted this thread I tried searching for answers so as to not waste anyone's time if these questions have been answered before but could not find anything. As my car warms up everything appears normal as the temperature reaches around 90 then the fans cut in and it drops to around 80ish then stays there for a while and will slowly make its way back to around 90ish again. If I slow down or drive very slowly for extended periods of say 5 minutes the temperature starts climbing to around 100ish but not over as I will normally take some form of action to help the car cool like stopping it. Today I had to move the car to let some other cars out from the garage and left it running to get the engine up to operating temp. I was checking it periodically to ensure it didn't Chernobyl or anything but noted it was doing the normal thing and went to 90 then dropped back to 80 the started to climb to 90 where it stayed for a bit then started to climb again without the fans cutting in even at around 100. I quickly jumped in to ram some cold air in by driving it (about 4 degrees here in Japan currently) I drove for about 1Klm and the temp was around 95 and went back home. Parked in the garage the fans were running and the car stayed at about 95. I cant work out if I have a late fan issue,thermostat,bleeding or whatever. The dropping under 90 has got be beaten. Cheers
First, check that all of your radiators aren't obstructed. I've had newspaper suck up against one. Second, you can force the right side radiator fan to always be On by shorting the two wires that go to the temp switch sensor on the top left of the right side radiator. Just unplug the black connector (easiest to remove wheel, then remove the plastic inner fender liner covers, then look for the two-wire-cable going to the top left of the rad) and jam a wire/paper clip into the open connections on the black cable connector once you've unplugged it. Leave the inner fender liners off. Reinstall the back right wheel and drive, noticing the temp and paying attention that the right side rad fan is always on. If the fan isn't on with the sensor cable shorted, then you have a fan issue. Easy to replace with generic. If the fan IS on and your temps are golden, then you have either a sensor or coolant level issue (a bubble in your rad can impact the sensor). Your one-time temp drop would possibly be from the thermostat opening up.
Thanks for taking the time to give a great reply with some decent options. Very appreciated thank you.
I think you have done this before, and was previously refered, but I will insist. Check if their is any air bubble inside water circuit. I have a similar problem and air on water circuit was the problem.
It sounds like you may have air in the cooling system. If the air gets to the impeller it will cause an air lock in the pump because it has no coolant to move. So try bleeding the cooling system and see what that does. There are 2 bleed screws on the right hand side (looking in from the rear) of the radiator feed tubes. Bleed the bottom one first and then the top one. As for the fans not coming on, try checking to make sure the fuses are not blown. If those check out ok then you may need a new sender. The sender is located on the top corner of the small half radiator on the right hand side of the engine bay.
Thanks for all the replies people I sorta feel that its leaning towards the bleeding issue as the thermostat is certainly opening on time and there is nothing blocking the radiators etc plus both fans are operating however sometimes not quite on time. Is there a thread somewhere on how to bleed a Ferrari 348 engine as I have never bled an engine in the last 52 years. Any link or words in the right direction is greatly appreciated.
It is pretty easy to do on the 348. Just did this 2 weeks ago. I used 2 long clear hoses attached to bleeder valve and ran them to a bucket. Initially used a pressure tester to bleed with car off since I only replaced a top hose. Then turned it on with full heat and cracked the valves open to flow until no air.
