360 Thermostat?

Are the fans going on

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Sounds like thermostat is sticking to me

 

I would start with fan circuit /fuses / temp sensor

First see if hoses to the radiator are hot

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+1

I think if the radiators were hot, at least one of the electrical contacts on the dual temperature switch on the RH radiator should have activated (at least one of) the fans.

As far as I can see, the lower temperature contact (92C) activates the left fan, which has one fixed speed, and the right fan on the lower setting. If the temperature goes to 97C, the right fan switches to high speed.

The fans have separate power sources and relays, so it's less likely to be a (multiple) fuse or relay issue. Because of this redundancy (in power and control), I would think that the issue would more likely be related to the thermostat or flow (pump?). BUT, unless fan operation is checked as routine maintenance, then I couldn't rule out multiple progressive failures. You may not have noticed one failure, but the second failure caused a complete "meltdown".

 

Let me explain - If thermostat is stuck .. the water is not ( mostly) making to the radiators
If the thermostat is working fine the hot water will be going to the radiators
If the fans are not going on due to a electric issues ( fuse, relay, fan itself, sensor) you will never cool the water and then you will eventually overheat
So if you measure the temp in the hose ( infrared gun) you should see if water is flowing
If flowing investigate fan/electric issue
If hoses are relatively warm while the engine coolant temp is very hot .. you probably have either a blockage ( could also be air) or a stuck thermostat
Get back with your findings

 

Seems like Ian and I posted at same time .. do some digging based on our posts and get back to us

 

Yep, check the basics first.

Update: The only common electrical fault I could find which would affect both fans would be the earth (ground) for the dual temperature switch. Sounds unlikely if you are not experiencing any other issues. A bad earth for the temperature switch would also affect your side markers (USA), RH horn, RH low beam headlight, RH turn light, luggage compartment light, etc.

 

Ian

First ..thank you for always jumping in and helping
...team work is the best

Remind me one sensor controls the both radiators ?

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There's a colourful blue temperature switch on the right hand radiator. I believe it has two "bimetalic" elements set at different temperatures.

Here's part of the circuit:


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Here's the full diagram for a later model 360 (Spider)

https://www.dropbox.com/t/be1EahVApW8tPdm3

but you need to be a rocket scientist to figure it out

 

Actually, I was experimenting with one a few weeks ago....

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+1

Feel free to point out my errors anytime I don't always get it right first time. I'm missing lots of practical experience.

Now that I think about it, I should have asked if the RH fan came on with the airconditioning cranked up to full cold. The AC system operates independently of the RH radiator temperature switch(es). A really large demand on the AC should even put the RH fan to high speed. If the RH fan comes on, it should check most of the circuits in the RH fan system. It just wouldn't check the temperature switch on the RH radiator.

Experts: Do you know if there are any easy ways of checking water pump output... without splashing hot fluid everywhere? Even if the thermostat and temperature switches were working, if the fluid is not circulating, I'd imagine a rapid temperature rise and the expansion tank filling pretty quick.

 

Im not sure if this was mentioned. What about simply looking in the coolant resevior. Wouldn't we see coolant flow if thermostat is working? No flow equals thermostat stuck

 

Does coolant flow through the reservoir or is it just an expansion tank where excess fluid flows as the temperature rises?

I assume the tank primes the pump but once the pump and rest of the system has fluid in it, does there need to be constant flow through the reservoir?

If you look at photos of the pump housing, there appears to be 5~6 pipes on it. Some of the pipes on the pump appear to be directly attached to the tank, so even if the flow was visible in the tank, it may not tell you if the thermostat was working. Coolant still flows through the engine even with the thermostat closed.

I’m not even sure if your cabin heating system would tell you if your pump was working. It has its own electric pump.

I can’t say I’ve seen a helpful 2D or 3D schematic of the system on these cars.

 

maybe this helps
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Hard to say. In your first photo, will there be constant flow through the smaller pipes going from the radiators to the tank? Could you distinguish the turbulence of this flow (if any) from turbulence from, say, the pump directly?

Look at these photos of the pump…

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What are the functions of all of these inlets and outlets? The more I look, the more I see. Seven?

 

We have to disregard those pics as they are for f430. Sorry My bad

 

360 radiator plumbing here (main flow), pump to radiator & back:

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Overflow:

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At least there seems to be only 3 pipes on the 360 tank (not including the one on the cap).

 

The pump cutaway diagram is hard to understand. I've labelled some of the outlets (to be confirmed).

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I don't see all the outlets/inlets

 

I don't know but I still think that once thermostat opens you would see circulation in the reservoir. But I been before