Thread: Check Engine Light TDI

Low coolant alarms have their own sounder and light. To be honest seems like a lot of work for not much point. Spend that time fixing rattles or stopping oil leaks or even better enjoying driving the vehicle.

Its so simple to put together your own low coolant alarm. I have had the kit with the plastic bung in top of rad that looks for ground through coolant. And considered the rangie cap sender. Plastic bung is not good and rangie cap with required circuit is over priced/complex.

I hope to use:
A float switch in header tank
A buzzer under dash
A dash light

Check engine light or the alarm LED in center dash would be ideal for visual.

Curious to know if the C.E.L is active in 300tdi auto, if so what triggers it?

they float switch is not as good as the thermostat bung.

firstly, you can still have coolant in your overflow tank but none at the top of the head. in which case your alarm will be useless.

secondly, when you go offroad and bounce around, the float switch will move around and probably sound the alarm on and off.

thirdly, i would much rather put a sensor on top of thermo housing with a plastic bung than drilling a hole in my expansion tank and trying to seal it.

fourthly, the plastic bung you get with the low coolant alarms from engine saver is not the same as the OEM plastic ones. it is far hardier and much less prone to coming off. never had a problem with it. i have a float switch in my shed along with the bits and pieces you said. but for the above reasons decided to just get engine saver.

there is another one which measures the metal temperature of your head, rather than coolant. that one is meant to be a top one too, if you dont want to tap into cooling system.

I have a float switch in the defender, a good one will seal better than a threaded bung. Its been years and no problems, no false alarms. It has notified me to a couple of leaks already and is backed up with a cylinder head temp guage.

I will do a similar set up in the D1

The problem I had with the plastic bung in my last D1 was that every time I had to change coolant the bung needed to come off and you takea a bit off the bung every time you undo it until eventually you round it. Much prefer a metal one.

Second I dont like the idea of electrical current being put through my coolant no matter how small.

Any ideas what the C.E.L light is for?

Originally Posted by manic

Any ideas what the C.E.L light is for?

Other markets where it was required at the time. Both V8's and TDi's got computer controls with self diagnostics outside of 3rd world countries.

I have just had one of these low water alarms fitted to my D2a.
I will ask what type/brand was fitted and where the sender is located when I pick up the truck on Monday.

Manic
Despite the naysayers I agree with you

On both my old 300tdi I ran a jay car float switch in the top of the header tank triggering an alarm - on my defender I also triggered a light on the dash can't remember which it was but
Was as you suggest an unused globe

If you look at the coolant flow in the 300 any drop in volume will show in the tank first
Theoretically it will drop the level in the header tank whilst maintaining top bung volume (due to pump pressure) up until level inntank is empty.

Furthermore there is nothing I want to do less than introduce an earth leakage into the coolant! I know many do it without excessive galvanic corrosion but if a float switch is do easy and effective why risk it!!!

I am yet to establish a coolant level alarm for my 2.4tdci but it is on the radar

Steve

I've decided to bring the C.E light into service.

Changed some bulbs in dash cluster and scoped out the C.E.L whilst I was there . Its a negative trigger and there is a pick up point behind the drop down panel under steering wheel.

RED Plug C209, wire is RS (red with gray stripe).

Its just asking to be used

In case any one's interested im going with

This buzzer
| RS Pro 12V dc Base Mount, Panel Mount Buzzer, 95dB |

Float switch
RSF76H050TV | Cynergy3 RSF70 Series Horizontal External Mounting Level Switch NO/NC Output | Cynergy3

Will ground float switch to the stud on inner wing which is right next to coolant header tank. Run f.switched output under dash to buzzer and tap into plug C209. Hook up an ignition switched +12v to the buzzer (fused) and its all done. Simples.