I’m experiencing some overheating on idle problems with my MK1 Eunos V-Spec and was looking for some ideas on what to look for, (not being mechanically minded).
Here’s the basics of the problem. When left idling the temperature gauge goes way up towards hot and eventually the water in the expansion tank starts to bubble and leak through the overflow pipe. The fan does not kick in at any point. As the car is fitted with A/C I turned it on and BOTH the radiator and A/C fans came on, is this normal? If so, does it sound as if my thermoswitch is the likely cause of the radiator fan not coming on?
Andy
Could well be a faulty thermoswitch. Disconnect it, it’s a single wire connector on the thermostat housing (follow thick black hose from top of radiator) then use a paper clip to short the terminal in the wiring loom to a metal part on the engine. With the ignition on the fan should run. Keep your fingers clear of the fan blades.
Robbie,
Thanks for the advice, I did as you suggested and the fan runs, it looks like a replacement thermoswitch is required.
Cheers
Andy
Just a quick update, I changed the thermoswitch tonight, went out for a good run and then left the car ticking over until the fan kicked in. Everything is now working as it should.
Thanks again Robbie.
Hi Andy, was on a run to the Bromley Pagent today, got stuck in traffic, thought fan would come on but it didn’t (instead coolent boiled in the bottle causing a huge cloud of steam out of my engine and serious loss of coolant).
I’ve been recovered home and after searching the forum found your post, I have done the same test on the small wire that goes into the thermostat housing and got the same result.
You posted that you replaced the thermoswitch, Is that another name for a water temperature sensor?, because I dont want to buy the wrong part. Is that the right part photo’d below?
Hi there, sorry to hear about your problem it does sound like the same fault I experienced and yes that look like the offending part. I brought the following: http://www.autolinkmx5.com/temperature-sensor-mx-5-16-mk1-fan-switch-376-p.asp which did the trick for me for £22.30 inc P&P. It’s extremely easy to fit.
Andy
Had same problem with mine, replaced the part with the new part as pictured above from autolink and still no luck. Shorted the switch with a paperclip and fan goes on as it should, but when temp goes up when idling fan does not kick in, any other common problems with wiring etc that could be the cause?
Maybe a blocked radiator not allowing the coolant to flow so the fan switch is not getting heated by the water. Are you getting overheating symptoms while driving or just no fan activity while stationary? How high does the temp gauge get?
Only tried whilst stationary at present as car not quite ready for the road yet. I think that there is some water circulation as the bolt that attaches the temp switch to the thermo housing is hot to touch so id assume this is not the cause. Have let the temp guage get 3/4 of the way to top of the dial before switching off as was worried about letting it get too hold, guess it ides for about 20/25 mins before temp starts going up.
1992 import. Just discovered that both fans have been wired in parallel to come on when the ac is on. Waste of £22 on a new sensor then!
As this is operated manually is there firstly any advantages of this, and secondly how do you undo it?!
Seems as though it will be a pain as have to keep an eye on the temp gauge all day long and turn the ac on when its getting a little toasty, but then remember to turn it off when hitting the a roads as cant imagine having the fans on at 60mph plus will do them or the heating system a whole lot of good. The more I work on this car the more convinced I am its had a bit of a dodgy past.Once again any help appreciated.
Thanks