328 Cooling Fans, What Temp?

Mine kick in at 195 i.e right in the middle of the gauge. Start by checking the coolant level & bleeding the system. If all is well & it's still doing 220 then you need to go through the system to find the cause which could be a number of things from a faulty temp sender/gauge to a bad fan switch.

What temperature is the car running at on the highway & is it stable or does it increase with the weather or when running harder i.e. it'll run hotter at 90mph than t does at 70mph? (because it shouldn't!)

I.

 

Dan,
As he said, first thing is to ensure you don't have air in the system, so bleed it (check the archives for the procedure, it's easy). If that is okay, and you have the proper level of coolant (6cm from the filler neck in the expansion tank when cold), then I would go ahead and replace the fan switch...they are cheap. Get a VW one for a 70's or 80's era Rabbit. Get the two pole version, and note that they are offered in two temp ranges, go for the lower one...kicks in around 180 versus 195.

Dave

 

My 87 328 fans come on at about 190 F. Yes, check for air in system then go for the temp switch replacement. Before you spend the money and just to verify a bad fan switch, remove the switch and put it in a pan of water on the stove. Throw in a thermometer, hook the switch up to a multimeter (set to the ohm scale...or a battery and a light bulb) and slowly raise the temperature. If it makes connection at 220 F instead of 190-195 F, you've isolated the problem.

 

Well, if you're quick, you can unscrew it and screw in another one, if you you have one, to minimize coolant gushing out. The switch is at the bottom passeger side of the radiator (at least it is on 308s)

Greg

 

The thermostat should have nothing to do with it... I'd suspect your gauge.

In my 308 the fans don't come on until the gauge reads 220... and that can cause a slight boilover when I stop.

What I did was pick up a cheap adjustable fan switch (since the fans are relayed you don't need one that carries many amps). I then used double tab connectors to wire it in parallel to the factory switch... so that if either one of them closed, the fans will work. (This also saved me draining the radiator).

Then I simply adjusted the new switch to come on where I wanted it to... about 180 on the gauge. Since then I've had zero boilovers or burping...

Total cost under $20... time under 30 minutes.

Bill

 

How stable is the temperature when yr on the highway & what temp does it run at?

On the basis that you've just put a new fan switch in you would think that will be telling the truth & its the gauge that's wrong.

Have you definitly bled all the air out (both from the radiator and the T'stat housing)? The temp sensor is in the top of the engine so if there was any air that could upset the reading somewhat.

I suppose its possible that the Thermostat is not working properly, is sticking & then opening suddenly releasing very hot water to the radiator which is then triggering the fans.

I'd suggest you find someone with one of those infra red thermometer gun things & see if you can get some readings of various parts of the system.

I.

 

Can you send a link or the details fo the fan switch? Any more details on the install?

 

Already mentioned but I'd bleed it first, on my 348 air bubbles caused a 10 degree late fan turn on as well.

Sent from my SM-G990U using FerrariChat.com mobile app

 

1st confirm gauge reading with an IR thermometer

 

You won't be able to test the high end in a pan of water

 

You have to be a bit careful when you post to a thread that hasn't been active for 16 years!!! The forum member you're asking hasn't been on the forum for over 5 years - they're not going to see your question.

I would suggest that when you search for a thread on a subject, choose the more recently active threads to add a question. I'd also suggest searching and asking in the 308/328 forum section, rather than this more general Technical Q&A section

Gordon