Coolant temp sensor (ECU)

Coolant temp sensor (ECU)

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Discussion

nawarne

Original Poster:

3,088 posts

259 months

Wednesday 13th August 2014
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Gents, just thought I'd share my experience/moment of panic!!

Was out on Monday and noticed the water temp creeping up in stop-start traffic in Lyndhurst (caravans/grockles/summer traffic). Became aware that the temp was creeping up and up...Got to do something about this thought I!

Today, I whipped off the airbox, ran the engine up, pulled the plug on the back/ecu sensor and fans kicked in as they should. I replaced plug and allowed engine to get to 98 degC...still no fans. Phoned Str8Six and spoke to Gordy - who confirmed my suspicion that the sensor was duff.

Had a new one - which went in, but sheared allowing the 'thermistor'(?) innards to essentially pull out of brass case. Depths of despair - thinking helicoil etc. Then noticed that the sensor screws into a screwed 27mm boss. Removed said boss, unscrewed remnants of sensor probe and replaced same with spare making good the boss and new/old sensor threads with PTFE tape. Jobs a good'un. Ran engine up, as soon as temp hit 94 degC, fan kicked in....Untold Relief.
Nick

Dischordant

603 posts

200 months

Wednesday 13th August 2014
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haha nothing beats that moment when it works =)

nawarne

Original Poster:

3,088 posts

259 months

Thursday 14th August 2014
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Cheers Darren.
You're right! I was in a blind funk until I thought laterally and tried the threaded boss, which came out fairly easily. With it out of the block, it was just a case of unscrewing the brass probe thingy.

Had visions of recovery etc. etc.
Nick

MrChips

3,263 posts

209 months

Friday 8th January 2016
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Thought i'd add to this thread rather than start a new one!

I've been getting odd readings on the dashboard of my mk2 Tuscan, (around 70deg on the dash and the first fan will kick in), and also some rough idling when starting from cold. Sods law that the time i borrow a laptop to read the ecu sensor, it starts fine and is reading fine.

So.. i'm going to change both sensors whilst it's not being driven. Anyone got a quick guide just to make sure i don't miss anything? My understanding is that i'll need to remove the airbox, and that the 2 sensors are under throttles 5 and 2? Been told to wrap the coil pack just in case of any fluid spill. What about refilling? How should I go about bleeding it once i've changed the sensors?

Also... where can I buy the sensors? Powers only list the one sensor, and tvr parts show one at £18 and one at £30?

A slightly boring topic I know paperbag

Thanks in advance!

nawarne

Original Poster:

3,088 posts

259 months

Saturday 9th January 2016
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Dave, you're right - don't understand why RG/TVR Heritage list 2 items.....OK, they 'feed' info to separate places - - but they are effectively doing the same job?

I think the RG item is supposed to be more robust, maybe the thought is that being at/nearer the rear of the engine it gets more heat stress?

In future, I'd replace the new sensor with thread lock, refill coolant and check for leaks...with engine running. I probably 'overtightend' the sensor body in the scenario quoted in the original post. Regarding covering the coil pack, I'd say why not?

To refill, Graham Varley suggests raising the front of the car, topping up the swirl pot whilst squeezing the hoses to/from the rad'. Then when you can no longer get any more coolant into the swirl, start engine and monitor level in the swirl - topping up as required - DON'T allow level to drop and draw air in. When 'stat opens, coolant will go to rad...the top hose to rad' will get hot. When the rad is hot, bleed any air from the 17mm(?) plastic nut on the top of rad' on the N/S side. A steady flow of coolant will indicate all air is out. Nip the plastic nut up, replace the pressure cap, go for a drive then check the level in swirl pot - That should be it!
Nick

Edited by nawarne on Saturday 9th January 10:26

NCE 61

2,385 posts

280 months

Saturday 9th January 2016
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The one with the flying lead M1275 is for the display, the M7000 of which were are two types Bosch and TVR (RG) is for the ECU fan control etc.