T350 Radiator fans not working

[black11s]

Hi Guys (and girls?),

Basically, my T350 is overheating in traffic. Its fine on the open road, but as soon as I get to a set of lights it starts warming up, and will then just get hotter and hotter until the coolant starts errupting all over the engine bay and I get plumes of steam coming out (along with the "oh my god its going to blow up" looks from passers by).

On first inspection, neither fan is coming on at either 92C or 98C.

I've read through a couple of the other overheating threads on here, and I have drawn the conclusion that I probably need to do one or all of the following:
1. Disconnect and clean the contacts for each fan with WD40, then seal with copper grease
2. Clean the temperature sensor and re-fit
3. Double check the fuses.

The fuses are eaasy - they are shown in the user's manual.
However, would it be possible for someone to post an idiot proof picture with a dirty great red arrow stuck on it, pointing out where the connectors and temperature sensor are please!

Also, all other suggestions very gratefuly taken on board.
I have already ordered a new expansion tank cap (just in case).

Thanks everyone.

[clive f]

dont have a picture, but the fan connectors are between the 2 fans just in front of the chassis, should be one connector per fan, 2 wires in each.

[black11s]

Thanks Clive. Are they the white plugs that lie on top of the fans?

Also, if I need to replace the water temperature sensors, are they a standard VAG part?

[UFO MATT]

Had the same problem with mine last year, I cut out the old connectors and replaced with new ones, only costs a few pounds for new and peace of mind.

[Quentin1]

Quick check to rule out any corroded connections/plugs:

Remove plug from coolant temperature sensor that starts/stops the fans. This is usually the back one (the one towards the passenger cabin) in the cylinder head. Both fans should run, if the plug is removed, since this is an error override. If they do, the sensor is probably knackered. If they don´t, you may have a problem in the wiring (corroded conenction somewhere).

Björn.

[RedSpike66]

To check that the fans work, with the engine running, remove the ECU Water Temp Sensor, as per Graham Varleys instructions... It's the one on the LHS of this photo, under Throttle Body #5. When you unplug that, both fans should automatically run. If not, you need to look at the connectors to the fans in front of the oil tank.

[black11s]

RedSpike66 said:

To check that the fans work, with the engine running, remove the ECU Water Temp Sensor, as per Graham Varleys instructions... It's the one on the LHS of this photo, under Throttle Body #5. When you unplug that, both fans should automatically run. If not, you need to look at the connectors to the fans in front of the oil tank.

Guys, this is perfect.
Many thanks. (Bjorn too)

As an update... I have checked the connectors to the fans, covered themn in WD40, given them a bit of a clean to no avail.
Tomorrow the cover's coming off the engine and I'll have a crack at the water sensor

[Hamish400]

I had a similar problem last year (2 fans not working). Turned out to be 1 x failed relay (in main fuse/relay panel under dash), and one x dirty fan wiring connecter.

Rgds
Hamish

[black11s]

Hamish400 said:

I had a similar problem last year (2 fans not working). Turned out to be 1 x failed relay (in main fuse/relay panel under dash), and one x dirty fan wiring connecter.

Rgds
Hamish

Is there any way of testing if this is the case?
Are these easy to come by?

[Hamish400]

Test the relays by substitution.

Try each fan relay, one at a time, in a position occupied by a similar relay, eg remove the dipped headlight relay and put the first fan relay in that position.
If the dip headlights still work with the fan relay in that position then that fan relay is working OK, and can be replaced in its original (fan) position.

Repeat test for second fan relay.

Replacement relays are probably available from any TVR dealer - I would expect them to be stock items;
OR you can mail order with care from Vehicle Wiring Products (select same current capacity as the original relay and the type with a diode fitted).

If a relay tests OK then the fault (for that fan's operation) lies elsewhere.

Rgds
Hamish

[black11s]

Guys, You've all been incredibly helpful, but I'm now feelijng like a complete muppet.
I consider myself (or did) to be of above average mechanical ability, but I can't remove the black plastic cover from the airbox.
The two clips are obvious, and I can get the "pipes" off the block, but not shift it much further. I'm scared or wrenching it incase I've unwittingly left something connected.

I've removed the pipe from the oil tank at the front, and the electric cable on the top too.

Any glaring omissions? Or should I just rip the thing off?

[Kernow67]

Theres a third clip between the airbox and the engine = roll your sleeves up and reach around from the front of the airbox. Its at the midpoint of the airbox on the engine side

Edited by Kernow67 on Thursday 1st March 21:42