Coolant Sensor(s)

B14, B172, B19/200, D16 engine, ignition, cooling, fuel & exhaust system, gearbox, variomatic, final drive... | Tuning: engine swaps, welded diff, clutch upgrades...
NO parts requests here, please use our V3M BUY & SELL corner
Post Reply
Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Coolant Sensor(s)

Post by Evoman » 17 Dec 2011 04:16 pm

It has been suggested I have dodgy coolant sensor, I tend to agree with the symptons but my problem is I cant locate. I know there are atleast two. One for the temperature gauge and coolant system but then a separate on the for "ecu". Is this correct firstly? and which is which? The hanes gives two located in the water jacket, the coolant temperature sensor and thermal time switch.

Any clear information would be helpful. I have order one, decribed in the book as "engine managment sensor" thats the one I want but which is it in my car.

Thanks alot
Chris
Image

pettaw
*** V3M DONOR ***
Posts: 1673
Joined: 15 Aug 2004 07:39 pm
Location: London, UK

Re: Coolant Sensor(s)

Post by pettaw » 17 Dec 2011 11:49 pm

Coolant sensor for the ECU is screwed into the head, on the side, towards the back end of the engine. There are two sensors there, and the coolant sensor is the one furthest forward. Don't get it confused with the thermal time switch for the cold start injector which has a plug which pulls on and off easily, whereas the coolant sensor has a clipped plug where you need to squeeze the metal clip to get the connector on and off. I would suspect if you need to change it you'll need to take the manifold off so you can get to it properly. It'll be pretty well seized into the head and need a good turn to get out.

BTW: Is this the car you had for sale in the 'offers' thread? Didn't see any mention of a running problem. What symptoms has it got?

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 18 Dec 2011 12:15 pm

Ye, unfortunetly it is :( Its only done it recently. The symptons are that it when first started from cold it will start and then die unless you use some throttle. It was idle bad for a few momments if you dont keep the throttle on. After that its fine, only when starting
Image

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 18 Dec 2011 06:01 pm

it also stinks of feul though when first started, is this just from the cold start injector? but as it runs odd, i was thinking it wasnt fueling right when cold.
Image

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 19 Dec 2011 06:07 pm

anyone? :) ordered a sensor and it arrives tommorow so I need to make sure it i get the right one.
Image

Nimminz
Posts: 1669
Joined: 11 Jun 2010 10:56 pm
Location: Durham City, NE England, UK
Contact:

Re: Coolant Sensor(s)

Post by Nimminz » 19 Dec 2011 09:46 pm

could possibly be a leaky cold start injector? or temp sensor for it?

try unplugging the injector, it helped when mine leaked
'88 360 +T LSD - sold
'87 760 TDI (D24TIC) - sold
'04 V40 D sport (F9Q, decat, Remapped, launch control)
'89 740 SE (b230ft, 12psi, V-cam, headwork, 'remapped', banded steels)
'86 340 DL 1.4

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 19 Dec 2011 11:17 pm

Im not sure it is that, because it stinks of feul when first started and it fails to run without throttle for a momment or two so that would suggest it doesnt keep feuling the main injectors
Image

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 26 Dec 2011 09:35 pm

pettaw wrote:Coolant sensor for the ECU is screwed into the head, on the side, towards the back end of the engine. There are two sensors there, and the coolant sensor is the one furthest forward. Don't get it confused with the thermal time switch for the cold start injector which has a plug which pulls on and off easily, whereas the coolant sensor has a clipped plug where you need to squeeze the metal clip to get the connector on and off. I would suspect if you need to change it you'll need to take the manifold off so you can get to it properly. It'll be pretty well seized into the head and need a good turn to get out.

BTW: Is this the car you had for sale in the 'offers' thread? Didn't see any mention of a running problem. What symptoms has it got?
What you describe seems alittle different to the car, they both have easy to reomve plugs. One is more in the middle of the head, in fact i removed the dizzy to put my hand under the manifold. Does that make sense?

But what I bought didnt match either of them, so ill be returning it
Image

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 29 Dec 2011 10:22 pm

Changed it, runs much better, still dodgy starting though
Image

pettaw
*** V3M DONOR ***
Posts: 1673
Joined: 15 Aug 2004 07:39 pm
Location: London, UK

Re: Coolant Sensor(s)

Post by pettaw » 31 Dec 2011 04:00 am

I hope you found it OK. From what you describe it looks as though you're looking on the wrong side of the engine. All the injection sensors are on the inlet side. They don't have any spade terminals, they're all weatherproof connections (Well slightly more weatherproof than spade terminals anyway :D) To give you an idea of the location, its very close to the feed pipe that goes from the head to the heater valve and heater core.

Evoman
Posts: 1688
Joined: 15 Sep 2010 10:47 pm
Location: Mid Wales

Re: Coolant Sensor(s)

Post by Evoman » 31 Dec 2011 02:26 pm

cheers pettaw, i found it and replaced it :)
Image

Post Reply