550 cooling problem fixed - finally

How hot did it get in traffic after you tried all of the initial fixes ?

I am surprised at the acceptable variation in water temp on these cars, I have also tried everything and still have an issue running hot.

 

Wow congrats.

Cooling system issues are such a headache to chase down and a potentially catastrophic problem. Glad you are sorted.

 

Thanks Roge, I'm also in a hot climate and have to avoid the city on hot days.

 

Very nice, I want to rewire my fans next as well. Can you post which parts you purchased and where you installed everything?

The OEM fuse board is overloaded with the fan and fuel pump circuits, and moving these to separate circuits is an easy win on these cars.

 

Hi Rodgerrr!

Very happy for your improvements. I had exactly the same problems like you. The new fans and wiring are worth 5x as much for me as I paid for them. By far the best and most important upgrad to any 550! I also actually love the sound of them. That makes it much easier to KNOW that both fans are working because you can hear that they start one after the other. And they sounds like real business! And it makes the AC blow better with colder air too. The 550s REALLY NEED this improvment. People and even the user manual say that it is «normal» that the temp can go higher and starting to approach the last line before the red. In my opinion and from my experiences, this is totally wrong. What happens is that when the engine is this hot, the oil temp start to follow, and the whole thing is like a heat pump, and it just gets worse and worse the longer you wait. I know because my red low oil pressure light came on whil idling in Paris for almost three houres and the gauge was almost on the red even with full heater and fan on inside the car. I was scared to death and I knew I had to let the engine run and revved it to 1500 rpm. to make the light go off while I was trying to get out of the horrendous traffic jams. To stop the engine would probably make the headgaskets blow...

After that I started to change the parts needed one by one to see what worked and what not. The new better fans are a MUST and they blow like you say twice as much air. But they also use more power.

Yesterday, I was at work in Saint-Tropez which is a tourist place on a kind of penninsular at the French riviera that can experience a crazy traffic as there is only one small road out of town and all cars seem to go to the same little town next to it (Sainte-Maxime). I stood in almost standstill traffic for about 2 houres! It was 32 degrees outside which is around 90 Fahrenheit. It doesn’t sound like alot, but when your exhaust manifolds are hot it makes the car seriously hot and I had to run the AC of full all the time to keep a comfortable temperature inside the car. I have with an infrared gauge measured the exhaust manifold wrap covers to be 270 / 520 degrees. Imagine when there are two of them, and the heat from the coolant is blown by the fans back onto the engine and that air blow the heat also from the exhausts down and under the car.... the car is killing itself when stranded like this for houres... I just «test started» the engine after one houre, and I noticed that the starter was a bit slower than normal. My opinion is that the new fans which need a 40A fuse (30A fuses blows right away), use more power than what the alternator can charge at idle. I have an extra small 45Ah battery in the trunk/boot parallell wired that helps, but I wish it was bigger. The temp in the engine bay is under these conditions right around 80 / 185 degrees. I have a digital display on the dash for that too. That means your battery is also that same temp. It is not good. So I want to install a digital volt meter to have a good control over the situation under these conditions. These cars are definately made to be driving at speed and not standing still. My temp did not go over the «straight up point» (90 / 195), but it was not going down either... So this lead me to believe that the car can still overheat if the outside temp is much higher and you wait longer... After one houre of continious fans on idling, I decided to stop and let then get a pause as the seller said that they were not made for continious running. The wiring and everything else was of course hot. When I opened the hood/bonnet, and let the engine run, then the heat went out and the needle dropped. That means the hood is very very bad for the cooling system as it is almost 100% tight around the wings and windscreen. I wish there could be some way to vent the heat out and upwards because then the car would not be as hot on the underside.

How long have you been sitting in stop and go traffic at 100 degrees F with your car?


Stay cool!

Erik


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