Member Since: 29 Nov 2021
Location: SW London
Posts: 261
Coolant temp sensor bypass again (with apologies)
I read that this has been done thousands of times, but on day 13 of ownership its a first for me so.....
I understand that a 5k ohm resistor is wired in parallel with the coolant temp sensor and engaged to start the vehicle only if the sensor is feeling chilly and sending a not now whilst I'm sulking signal.
I have a reasonable aptitude to heavy metal but am certainly no sparks and having bought these two versions of a 5k ohm resistor here's the question.
WHICH ONE DO I USE?
Thanks
Pete
6th Dec 2021 1:45 pm
matgriff
Member Since: 16 Sep 2019
Location: Newcastle Under Lyme, Staffs
Posts: 171
You just need the small 1/2watt resistor, you're not dissipating any power. That gold aluminium clad resistor will dissipate around 50 watts when fitted to a decent heatsink.
Mat2005 TDV6 SE Auto
Cairns Blue
6th Dec 2021 6:20 pm
Register
Member Since: 29 Nov 2021
Location: SW London
Posts: 261
Mat
thanks for that.
I assume therefore I just use one of the thin wire ones?
Hope so as I extended the ends and added some shrink wrap and bullet connectors.
Also found a use for the strange clamp thing I found at a boot sale.
Pete
6th Dec 2021 6:56 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
You don't want to leave the resistor connected all the time. (only while chilly starting)
So people fit a push button inside
Instructions, pictures, links to things to purchase below
Member Since: 29 Nov 2021
Location: SW London
Posts: 261
Pete
Thanks, I found this photo on @Flapper's thread. Maybe his switch.
Looks like a good out of the way location for my momentary switch.
Pete
6th Dec 2021 7:41 pm
Devon Z
Member Since: 14 Nov 2019
Location: Brixham Devon
Posts: 238
I’ve just done this, fitted my press button on the left side of the steering column where the electric column adjustment switch would be.
Not had to use it yet 😳Steve
*2005 RR Sport 2.7tdv6 HSE. Current project.
*98 Volvo V70R FWD, owned 14 years, future project.
*99 BMW Z3 30k miles owned from new.
6th Dec 2021 10:05 pm
Register
Member Since: 29 Nov 2021
Location: SW London
Posts: 261
Steve
any chance you could send a photo?
Thanks
Pete
7th Dec 2021 1:45 pm
Flapper
Member Since: 04 Feb 2015
Location: Gloucester
Posts: 329
Starting using the temp booster switch and no glow plugs
Here is how to start you car on a cold -1 to -3 morning
1 use glow plugs just in case 1 or some are working
2 try starting ..... if it doesn't start turn off
3 push the temp booster button (resistor) and use glow plugs as above. (temp gauge will rise)
4 start up ( may be lumpy )
5 push temp boost button again to remove the resistor from the circuit (temp gauge will fall)
I would like to see what the limit to this work around is but need some one in a colder climate to have a go.
Maybe Christian from LR time could try my solution as they may get colder winters
7th Dec 2021 2:04 pm
Devon Z
Member Since: 14 Nov 2019
Location: Brixham Devon
Posts: 238
Register wrote:
Steve
any chance you could send a photo?
Thanks
Pete
Sure Pete here you go, it’s momentarily switch so push and hold.
SteveSteve
*2005 RR Sport 2.7tdv6 HSE. Current project.
*98 Volvo V70R FWD, owned 14 years, future project.
*99 BMW Z3 30k miles owned from new.
7th Dec 2021 2:46 pm
Register
Member Since: 29 Nov 2021
Location: SW London
Posts: 261
That looks terrific.
I doubt I’ll get it that tidy but I’ll give it a go.
Thanks
Pete
7th Dec 2021 3:41 pm
Flapper
Member Since: 04 Feb 2015
Location: Gloucester
Posts: 329
That looks great!
I found when starting you only need the switch pressed for only 4/5 seconds the temp gauge only just starts moving (still in the cold bit) then start the engine and click off or let go in your case.
On the other end of the cable make sure you leave enough slack for the engine to giggle around so the cables not pulling on you new joint.
F
7th Dec 2021 4:05 pm
Devon Z
Member Since: 14 Nov 2019
Location: Brixham Devon
Posts: 238
Thanks for the kind words guys it was straight forward enough, I ran the cable along the top of the engine following the engine loom then it comes out rear drivers corner and then pops though with the brake pipes
Into the plastic box where’s a nice grommet in the bulkhead, that comes out nicely under the dash only thing to be careful of here is the steering column going round, make sure the cable stays out the way of it.
SteveSteve
*2005 RR Sport 2.7tdv6 HSE. Current project.
*98 Volvo V70R FWD, owned 14 years, future project.
*99 BMW Z3 30k miles owned from new.
7th Dec 2021 4:40 pm
Register
Member Since: 29 Nov 2021
Location: SW London
Posts: 261
Flapper, Steve
thanks both for your input. Invaluable. I'm off to the Alps on 26th so will put this to the test.
Hopefully the engine will start without too much 'giggling' around.
Pete
7th Dec 2021 8:44 pm
Devon Z
Member Since: 14 Nov 2019
Location: Brixham Devon
Posts: 238
No problem, hope it works and you have a great trip.
SteveSteve
*2005 RR Sport 2.7tdv6 HSE. Current project.
*98 Volvo V70R FWD, owned 14 years, future project.
*99 BMW Z3 30k miles owned from new.
7th Dec 2021 9:41 pm
Devon Z
Member Since: 14 Nov 2019
Location: Brixham Devon
Posts: 238
Finally had cold enough weather down here to try it out😄 garden temperature was showing -1 this morning so got in the car and outside temp showing 0 pressed the button and held till the needle just started to rise then flicked the starter and she fired first time, low idle for about 20 seconds then normal no excess smoke like I had when I used the hot water method last year.
All in all pleased for a work around I may only need once or twice a year👍Steve
*2005 RR Sport 2.7tdv6 HSE. Current project.
*98 Volvo V70R FWD, owned 14 years, future project.
*99 BMW Z3 30k miles owned from new.
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