Coolant light and rev counter issues

[clift_d]

We're having some issues with our coolant light and rev counter.

The coolant light has started coming back on after a couple of minutes of running. The coolant level in the tank is fine, the temperature doesn't rise above normal, and we can get heat output at the front of the van so it seems like the coolant system is working. However the rev counter is also now playing up. The needle drops back down to zero revs for periods before suddenly bouncing back up again to the correct reading.

I'm guessing that this is an earth or other connection problem at the console, but is there anything else I need to consider before I try to hunt this down?

Thanks

[AdrianC]

The coolant level in the tank is fine

Both tanks?

we can get heat output at the front of the van so it seems like the coolant system is working.

I'm not sure that's a particularly valid test, tbh. Take the upper grille off, and make sure the rad is even temp top and bottom. Keep it idling until the fan cuts in and out again. THEN you know it's working.

But, yep, sounds like it might be electrical. Is the rest of the dash behaving?

[clift_d]

Both tanks?

Doh, never thought to check the expansion tank - stupid as that's where the sensor is!

I'm not sure that's a particularly valid test, tbh. Take the upper grille off, and make sure the rad is even temp top and bottom. Keep it idling until the fan cuts in and out again. THEN you know it's working.

Okay, sounds sensible to check this as well.

But, yep, sounds like it might be electrical. Is the rest of the dash behaving?

We had one issue recently with the headlights staying on main beam and not wanting to switch to dipped - this resolved itself the next time we turned on the van - thought it might be dodgy contacts on the indicator arm - if it is electrical then this would make sense as well.

[AdrianC]

Both tanks?

Doh, never thought to check the expansion tank - stupid as that's where the sensor is!

The expansion tank is the one inside the catflap, which varies in level.
The header tank is the one with the sensor, inside the engine bay, which should always be brim-full.

We had one issue recently with the headlights staying on main beam and not wanting to switch to dipped - this resolved itself the next time we turned on the van - thought it might be dodgy contacts on the indicator arm - if it is electrical then this would make sense as well.

Yeh, that's more likely to be sticky contacts - are your headlights relayed? If not, might be worth doing that sooner rather than later, save you replacing the stalk just yet.

[clift_d]

Okay AdrianC was right first time.

I'd not twigged to check the coolant level in the expansion tank - it's in the middle on the right here, which was on the minimum even though the filler tank (behind the cat flap) was showing full.

It does beg the question though, why is there a filler tank at all if you can't use it to add coolant to the system, or have I got a blockage somewhere?

All this still leaves me with a 'bouncy' rev counter and sticky contacts on the headlights dip switch.

[AdrianC]

It does beg the question though, why is there a filler tank at all if you can't use it to add coolant to the system, or have I got a blockage somewhere?

Assuming you've got a healthy blue Dalek, you can. Keep that filler tank to the right level, and the main header won't ever dip down below full.

[clift_d]

Just to revisit this one...

Turns out the reason the coolant level was dropping in the expansion tank was a defunct dalek cap. All the coolant was ending up in the filler tank behind the cat flap meaning that the level kept dropping in the expansion tank and the sensor light kept coming on. I've just fitted a new OEM cap from brickwerks and took the van out on errands for a couple of hours and everything seems to be in order again - the temperature even seems to sitting at a lower level than before once the engine has heated up.

[seeker]

I've got the same rev counter problem, but I don't think it is in the 14 pin connector. Did you ever trace the fault?

[clift_d]

No, I haven't had a chance I'm afraid.