HELP!! 308 Overheating

My guess is that if they had just changed the antifreeze it may have some air in the cooling system. Something you could try yourself is to bleed the radiator. First take off the coolant fill cap. The fill is at the reservoir can behind the engine, there is no fill at the actual radiator. Check the level, add some if it is low, leave the cap off. Then, on the passenger side of the radiator, forward of the spare tire, near the top, you will see a small knurled nut. That's the bleeder screw. Open that up a few turns, it doesn't need to be removed, just opened up a bit. You will need a pair of pliers. You should get straight coolant coming out. If you get any air, just leave it open until all the air is out. When it is all coolant, snug it back up.

There is also a bleeder screw on top of the engine, also on the passenger side, on top of the thermostat housing; it looks like a brass bolt. check that one also for air and then top off the coolant. The side of the reservoir has markings to indicate where the level should be. Roughly 1/2 to 2/3's full. Put the cap back on. Next to the cap you will see a small clear plastic hose that runs down. This is where you saw that jet of steam coming out. When the coolant is overfull or the system pressure gets too high due to overheating, it will burp out the excess through this hose. The burning smell was probably just coolant splashing onto the exhaust.

Next would be to check the cooling fans. Just start the car up and let it warm up in the driveway. When the car gets up to around 190° or so you should hear the fans come on. It should take around 15-20 minutes or so depending on the outside temperature. If the fans don't come on check the fuses. The fuse panel is behind the lower portion of the dashboard on the passenger side. That whole portion of the dashboard is just a cover.

If you've got all the air out of the system, the coolant topped off, the fans come on and it doesn't overheat in the driveway - Go ahead and take it for a spin keeping an eye on the temp.

Good luck! If the temps stay normal then it was just air in the system and you have just completed your first Ferrari repair.

 

Pete nice description. Also he might want to make sure that the water pump belt is turning and possibly want to get a new rad. cap but I assume it was not overheating before he got the car. Enjoy the ride.

 

I am chasing a running warm condition on one of my 308s as well. I have repaired almost each one of my 308s from running hot before. It can be a pain.

Check for obvious leaks or obsrtuctions in airflow. If you have a leak find it and repair it. If you can't seem to find it rent a cooling system pressure test kit at Autozone or Advance Auto. Pump it up to pressure and find the leak.

First I would replace the radiator cap. Cheap and easy to do. Get a 1.1 Bar cap.

I would pull the thermostat and put it in a pot and heat it up. Make sure it opens. If you don't want to remove it then you can run the car and make sure the radiator get hots. You can also feel the top hose pulsate slightly when pressure is applied after the thermostat has opened.

Make sure the cooling system is bled properly. Air in the system will cause fast temp spikes. The temp gauge will go from 195 up to 230 quickly and then back down if there is air in the system.

Water pump. Easy to check. With the radiator cap off on the header tank start the car and watch in the tank. You should see a steady stream of water coming in the header tank. Rev the engine slightly and make sure you see the increase of water flow.

Belt and water pump rotation. With the car running look at the water pump and water pump belt. Make sure both are rotating correctly. If you feel you can see the tensioner pulley moving mark the top of it with some white paint when the car isn't running and restart it and recheck.

Now onto front radiator fans. The best way to test this is to remove the 2 wires on the radiator fan switch. It is on the passenger's side of the car at the bottom of the radiator next to a coolant hose. You will see 2 spade electrical connections on it. Remove them and attached the 2 wires together with a jumper. Turn the key to the 2nd position. The fans should come on. Both of them.
Now check to make sure they are blowing accross the radiator. It is important that the fans are turning the correct way.

If all of this checks out you either have a bad sending unit or coolant temp gauge or the radiator is clogged. You can check the radiator by getting an infrared temp gun and shoot temps at the radiator inlet and outlet. You should see a 25-30 deg. drop in temps between the to readings.

Anyway this should help you out. If you need more detail on the gauge or sending unit let me know. I have yet to see a bad sending unit but I have heard of them going out.

 

This sounds very similar to what was happening to my 328 last year. Basically the rocketing temperature was caused by a loss of coolant which in turn was caused by a weak cap on the expansion tank.

Suggest you get the cap tested & if its not holding at least 1 Bar then that's probably your problem. You should be able to get a standard 1 bar cap that will fit at your local auto parts store.

Once you rule the cap out (i.e. if replacing it doesn't solve the problem) then I'm afraid you are looking at water pump or radiator problems - but I'll bet you its just the cap - they don't last more than a few years at best.

The coolant level in the tank should be 6cm below the bottom of the filler neck i.e. the tank should only be about half full when its cold. As others have said, bleed from the radiator and the thermostat housing to eliminate the air and expect to get several lots of air out of the system. Make sure your heaters are working.

HTH

I.

 

Very good description guy's,
but don't for get to open the heater switch inside the car so that the water flow is not blockt.Rob

 

Rob makes a great point. Don't forget to open the heaters when bleeding.

 

So Jawad,
I'm kind of curious as to what you found out today.

 

I second the bleeding and the radiator cap. The previous owner of the first 308 I bought spent a lot of money on the cooling system trying to cure overheating before he discovered the cap was bad. I had a similar problem with the an 85 QV I owned later, so bought a new cap. Since I was thinking of showing the car, I bought a Ferrari cap but the problem continued. Eventually, we tested the new cap and it was bad. So, do not buy a Ferrari cap. Bring the cap you have to a Nappa store, tell them you need one with 1.1 bar or so. I believe there is a BMW cap that matches perfectly. Anyway, a bad cap causes all kinds of problems. Without pressure, the water boils at a much lower temp, doesn't flow right and heats up more quickly. The smoke and smell you got was probably from antifreeze on the exhaust.

Dave

 

these cars are old and the hoses are old and with engine off and cold look at every hose and squeeze and see if puffed out or feels spongy...with engine hot and running...look for drips, smoke hissing...take your time and a flashlight and look,look, look....on three seperate trips out to the hamptons with a girl I blew a rad hose sitting in GCP traffic....not fun..and not a smart way to go about replacing your hoses..pressure test the system..the expansion tanks are very old and can get pinhole leaks...I had mine "resealed" many times and there can still be problems. hot steam and fluid shooting out by the rear drivers tire (LHD) is overflow from the expansion tank...tank when cold should have a level about 6 cm from top...no more..or it will boil over, smoke and spit it out. bleed the thing or air..there is a bleed screw onthe rad and also on the thermostat housing...let lots of coolant "piss" out of those holes....
BTW// where are you parking her and what is her colors? Welcome to NYC Ferrari ownership....hang on tight!