355 overheating-major or minor problem?

Does not sound like head gasket. I would check 1) fan and temperature switch, 2)thermostat, 3) waterpump, 4) coolant change and bleed again.

 

It could be a number of small things, I doubt it is a headgasket. Driving in traffic overheating is not worth the risk. We are 30 minutes from the hamptons. I am going to PM you the number of a tow truck and my cell phone number if you get stuck in the hamptons.

 

Make sure the coolant level (when cold) is 6 cm from the top of the filler neck. Most likely one of the following has happened:

1) One of the 30 amp fuses blew for the left or right radiator fans. A common issue, and the fix is to replace the radiator fan...they start drawing excessive current as they age and will blow fuses more and more frequently.

2) The left side radiator fan thermoswitch has failed. This causes the left side fan to never come on, until the thermoswitch is replaced.

3) One of the fans has failed outright....either bad motor or fan is broken/detached from motor.

 

The fan switch is the most common failure, sounds like the primary cooling fan isn't kicking on when it needs to. If you ignore it for too long the headgasket will let go...I've seen it happen more than once.

If it were the headgasket, if you started the engine with the coolant bottle cap off (when cold) it will immediately start blowing water out.

Shouldn't be a real big issue to repair.

 

If it is not a blown fuse, my guess would be it it the LH radiator thermal switch (top of the radiator). It is responsible for turning the LH fan on.

 

Would anyone have knowledge as to whether FIAT uses the same thermoswitch on any of its cars?

Local F agent needs 2/3 weeks to bring one in from the factory.

 

I have not heard of anyone finding a cross reference to another car. The threading seems the same as many other brands of cars, the issue is the Amp weatherproof connector used. Best shot would be to take the thermoswitch to an import autoparts store and ask them if they recognize, as matching another car.

 

@f355spider
Thanks for the suggestion ( I think I will hit the FIAT agents and Alfa Romeo

 

I had a very similar problem just after a major service. I tried wiring in a manual switch and got the fans all running. The car still overheated. The shop said it was the thermostat. Billed me plenty. Maybe they damaged it during the major. But I suppose, as this is a 355, it wouldn't be impossible for yours to have failed all by itself!!

Good luck! Hope it's just the switch or a fuse. (I did the fuse swap to check mine. They were both good, of course.)

 

Makes sense...if the thermostat is stuck closed, the coolant is not going to reach the radiators. The fans are not going to help in that situation. I had the opposite happen at my major service, the dealership installed a new thermostat, and it stuck open....car always ran too cold. I took it back a week later and they replaced it at no charge of course. Stuff happens.

 

I've owned two 355s -- both a 1995 and a 1999 -- and here's my 2 cents:

The 355 runs a little warmer than we'd like. On the highway, cool as a cucumber. In traffic, the needle creeps along. Mine used to go almost to the red but I had a problem with my thermostat, which I rectified. I replaced both the thermostat switch and the thermostat itself. Now, the car still runs warm in traffic but not nearly as bad as before. The needle shouldn't be farther than the 2nd white line past 12 o'clock. It should actually behave between the first and second white lines to the right of center at worst.

The air conditioning actually keeps one of the fans on all the time. This is a good thing.

The first fan is controlled by the thermostat. It should kick on at 190. The second fan is controlled by the Motronic. It kicks on afterward if the temperature continues to climb.

The fact is that at least one fan should be on all the time if the temperature is above 190. At least one fan should be on taking you all the way down to under 190. They take turns kicking on and off. I actually never understood this nonsense.

The easy thing to do first is to check not only the thermostat itself but also the thermostat switch. These are pretty inexpensive parts, so you may just want to replace them outright. If the problem persists, then you may investigate other possibilities, such as removing the radiators and sending them to a radiator shop to be blown out. That, however, is a more Draconian avenue at this point.

The 355 *will* run warm in traffic, but under normal "warm" conditions, the needle should still be safely well away from the red zone.

 

Dave,
The left fan comes on at 190F as you stated, and the right fan comes on around 203F. They get their temp readings from different locations too. Left comes from the left radiator, as you mention, the right gets its signal from the Motronic water temp sensor near the oil filter housing on top of the engine.

In 95F degree weather with stop and go traffic, my temp gauge is between 190F and the next white hash mark to the right. It never actually reaches that second mark, usually hovering between the two...and often dropping and staying right at 190F most of the time. As you state, the fans cycle on/off in a rather peculiar manner....but the temps stay stable, never overheating.

 

Thank you for the input.

Having read the multiple responses I think I am sitting with a switch issue as opposed to a thermostat issue as the car stays under midway on the gauge when at speed (and as low as 1/4 on the highway) and at idle in traffic it cooks, therefore would that not indicate that the thermostat is working properly?

I think I shall take the switches out and boil them to determine at what temperature they might open at and complete the circuit (if they do).

 

Not necessary. You should be able to tell very quickly which fans are or are not coming on, after starting and letting the car warm up. If the fuses are good (you checked them right?), then it most likely is one of the switches. The left switch most commonly fails, as the left side seems to run the most. If the right side Motoronic water temp switch was not working it would most likely throw a Check Engine light.

If the fuse (s) are blown, you need to consider replacing the fans...the motors, as they age, start to draw excessive current, causing the fuses to blow. I replaced mine recently and have a thread on it, along with an inexpensive source for oem fans.