Overheating issues

Overheating issues

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Discussion

Sandgrounder

Original Poster:

563 posts

144 months

Saturday 21st May 2016
quotequote all
Not been on here for awhile as all has been good in TVR world. However, went for a drive on the hottest day of the year, and whilst parked in gridlock, noticed increase on temp gauge. Normally, my car is fixed smacked bang in the middle of the
Gauge with no fluctuation. Anyway, turns out fan is not coming on. So, I have done some quick checks, I have put a fly lead across the pins on the otter switch (if that's what it is called) with engine running. I was hoping this would switch the fan on, but nothing. Does this indicate a broken fan?

Can't get anywhere near to fan to check it. I assume the bonnet needs to come off for that!

Thanks for any guidance.

v8s4me

7,240 posts

219 months

Saturday 21st May 2016
quotequote all
Pull the leads off the otter switch and join them with a spade fuse. Does the fan come on?

Yes = knackered otter switch.
No = connect the fan directly to a live feed and separate earth. Does it spin?

Yes = check the fuse under the dash.
No = suspect the fan.


Sandgrounder

Original Poster:

563 posts

144 months

Saturday 21st May 2016
quotequote all
Thanks, that all sounds logical.
I'll have a look tomorrow.

phillpot

17,114 posts

183 months

Saturday 21st May 2016
quotequote all
Sandgrounder said:
I have put a fly lead across the pins on the otter switch (if that's what it is called) with engine running.
You need to join the two wires together, not the connections on the switch?


My car has the fan on the "air on" side of the radiator but there are some connections to it near the crossmember that supports the swirl pot, near the horns, that are prone to corrosion and general failure scratchchin

RayTVR

1,040 posts

143 months

Saturday 21st May 2016
quotequote all
Wiring near front of crossmember would be favourite - otherwise try swapping the relay (fitted in the fuse panel)

GreenV8S

30,186 posts

284 months

Saturday 21st May 2016
quotequote all
Check the fan is physically free to spin, and check the fan fuses.

Sandgrounder

Original Poster:

563 posts

144 months

Sunday 22nd May 2016
quotequote all
Good advice Gents. I took a few photos, but haven't got the IT skill to get them off my phone onto this laptop, particularly as my mate has just loaded Windows 10 onto it last night.

Anyway, I dropped the fuse box into passenger footwell, and straight away noticed a molten mass of plastic where a 25 amp fuse used to be. I pulled it out and replaced it. Then took the wires off the otter switch and joined them together, ignition on, and the fan sparked into life!!.

Don't know what caused the fuse to melt, so will need to keep an eye on it, but car now back in action.

Strangely, despite condition of the fuse, once I scraped some carbon off one of the pins, it still had continuity!!
The unsurprising thing was that this 25 amp fuse is not allocated to anything according to the bible for S3's, but I keep hearing that TVR wiring is a law unto itself.

So, for now, all is sorted. Thanks to all for the help.




GreenV8S

30,186 posts

284 months

Sunday 22nd May 2016
quotequote all
That probably indicates that the fuse had a poor contact with the fuse holder which was causing local heating. This can damage the fuse and holder so make sure all the contacts are clean and that the new fuse is still a tight fit in the holder.

Sandgrounder

Original Poster:

563 posts

144 months

Tuesday 5th July 2016
quotequote all
Evening all. Well, I've not been using my TVR much lately, but it has been ok temperature wise while I have used it. Unfortunately, this weekend, I got stuck in a traffic jam near home, and the temp gauge started rising again.

Got home, popped the bonnet, alas no sound of fan spinning. So in a bad mood, just put the car away in garage, and as soon as switched ignition off, volcanic eruption of coolant on the garage floor.

So, I would imagine fuse is melted again, but didn't check. Assuming it has, does this indicate a problem with the fan, drawing too much current? Electrics are not my speciality as you can probably tell.

I know I will have to take the bonnet off to even see the fan, but don't want to swap it unless I know that is the problem. Is there anything else to consider before fan transplant? Is there a check I can do on the fan to see if it is faulty?

Thanks

v8s4me

7,240 posts

219 months

Tuesday 5th July 2016
quotequote all
Have you checked the relay?

Sandgrounder

Original Poster:

563 posts

144 months

Tuesday 5th July 2016
quotequote all
I didn't know there was one? I'll look at the bible to see, but as the fuse was not as per bible, it is difficult to know what to believe.

Also, if it has a relay, how would I check it?

thanks

Alan461

853 posts

131 months

Tuesday 5th July 2016
quotequote all
Given what you said about the fuse holder That's the first place to look.
All S models have a fan relay according to the bible, S3 has 5 relays can't help with which one but you can find out by pulling each relay until the fan stops.

v8s4me

7,240 posts

219 months

Tuesday 5th July 2016
quotequote all
Sandgrounder said:
...Also, if it has a relay, how would I check it?...
If it looks like this...



...it's knackered laugh

Sandgrounder

Original Poster:

563 posts

144 months

Tuesday 5th July 2016
quotequote all
I'll take a look at fusebox/relays at the weekend. If I can't see anything obvious, I have some time off coming up, so bonnet removal is on the cards!! Watch this space!!

Thanks guys

GreenV8S

30,186 posts

284 months

Tuesday 5th July 2016
quotequote all
v8s4me said:
If it looks like this...

...it's knackered laugh
And the terminals in the relay socket are probably toast too.

ClassiChimi

12,424 posts

149 months

Tuesday 5th July 2016
quotequote all
v8s4me said:
If it looks like this...



...it's knackered laugh
I know your trying to help out a fellow owner, thumbup
But that's hilarious biglaugh

LawrieS

338 posts

116 months

Tuesday 5th July 2016
quotequote all
Woah, step away from removing the bonnet.

I had the same problem.

The fan connects to the loom just underneath the cross member, there is a two pin plug which I suspect is your problem, chop this off and run clean wires to the battery for testing.


I thought my plug looked ok until I had it on the bench:


I too had been nursing it in traffic for the year, swapped it for
A choc block (it and all the tools require had been in the boot sinve I've owned the car) it's fine now.


Which reminds me I must swap that for a real plug...

GreenV8S

30,186 posts

284 months

Tuesday 5th July 2016
quotequote all
LawrieS said:
swapped it for A choc block (it and all the tools require had been in the boot sinve I've owned the car) it's fine now.
Without some strain relief and protection from the elements, that'll soon become even less reliable than the original connector.

LawrieS

338 posts

116 months

Tuesday 5th July 2016
quotequote all
LawrieS said:
Which reminds me I must swap that for a real plug...
wink



wedgeman

1,326 posts

243 months

Tuesday 5th July 2016
quotequote all
If you would like any assistance please feel free to give me a shout - I'm only 20 mins away and would be happy to help out thumbup