Temp guage going weird

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flookyk

flookyk

Active Member
Posts
177
Location
CO Durham
I have a 1a998 DSE.

After recently changing a coolant/ heater pipe at the rear of the engine, got it all working again but have noticed it was still loosing water somewhere.

Cannot see any signs of a leak apart from it being "wet" at the front of the engine where the thermostat housing is at.

Kept on topping the water up and keeping an eye on it to see of any other leaks but can see none (the radiator was changed a few months ago and no problems).

This morning on the way to work, the temp gauge started acting weird.
After a couple of miles the temp went up to the top so I stopped, turned off the engine and restarted.
The temp came back down to normal, so I set off again to work.

On the way the gauge would go up to the top, then come back down again as though something had "sorted" itself.
The radiator fan is spinning OK.

One thing I was wondering is has anyone had experience of the thermostat starting to fail with these symptoms?
When I stopped (with the gauge at high) I felt the two top pipes in the radiator the offside one was cooler than the nearside one but you could touch both of them.
 
Thermostat maybe on it's way home. Change it and look at the small heater pipe that you remove to get at thermostat O'ring may have failed.
 
Well changed the thermostat today, refilled with water and ran the engine until it warmed right up.
Checked the pipes to the radiator and the passenger side one heated up first and got hot, then later on the drivers side one heated up as well.
It seemed OK so started moving the car a few yards back and forwards and the temp started going up to the top of the marked section, then eased a little.

Continued to run it and it started going right to the top of the marked section.
I am letting it cool down then will check the coolant level and see if it needs topping up.
You could see the level looked OK but it took quite a bit less to fill it up then came out when drained the radiator, so may have a air blockage somewhere.

Any ideas where the best place on the system to get rid of any air from the system.

Of course, when draining the system in the first place I forgot to undo the cap on the bottle first and on removing the radiator drain plug got drenched when it camout under pressure.

UPDATE: Just been to check the levels when it has cooled down again and it was around a third of the way up the bottle, so topped it up again and will retest it tomorrow.
 
Last edited:
flookyk said:
Well changed the thermostat today, refilled with water and ran the engine until it warmed right up.
Checked the pipes to the radiator and the passenger side one heated up first and got hot, then later on the drivers side one heated up as well.
It seemed OK so started moving the car a few yards back and forwards and the temp started going up to the top of the marked section, then eased a little.

Continued to run it and it started going right to the top of the marked section.
I am letting it cool down then will check the coolant level and see if it needs topping up.
You could see the level looked OK but it took quite a bit less to fill it up then came out when drained the radiator, so may have a air blockage somewhere.

Any ideas where the best place on the system to get rid of any air from the system.

Of course, when draining the system in the first place I forgot to undo the cap on the bottle first and on removing the radiator drain plug got drenched when it camout under pressure.

UPDATE: Just been to check the levels when it has cooled down again and it was around a third of the way up the bottle, so topped it up again and will retest it tomorrow.
Click to expand...

Did you follow the refill procedure in Rave? Doesn't sound like it, they can be tricky but once you know how, it's easy when done correctly.

Refill
8. Ensure sufficient coolant solution is available.
See LUBRICANTS, FLUIDS AND
CAPACITIES, Information.
9. Inspect radiator drain plug ’O’ ring, renew if
required.
10. Fit drain plug to radiator. Tighten to Max 6 Nm
(4 lbf.ft)
11. Remove safety stands. Lower vehicle.
12. Disconnect radiator bleed hose at the radiator.
13. Blow through hose to clear any residual coolant.
Reconnect hose.
CAUTION: If radiator bleed hose is not
cleared of coolant, air may become
trapped at top of radiator during refill,
leading to subsequent engine overheating.
14. Fill expansion tank until coolant is level with
base of neck.
15. Start engine, continue filling at expansion tank
until coolant level stabilises at the ’COLD
LEVEL’ marking.
16. Run the engine until the thermostat opens (top
hose becomes warm).
17. Stop engine, allow to cool.
18. Check coolant level, top-up as necessary.
19. Refit expansion tank filler cap.
 
Last edited:
flookyk said:
Well changed the thermostat today, refilled with water and ran the engine until it warmed right up.
Checked the pipes to the radiator and the passenger side one heated up first and got hot, then later on the drivers side one heated up as well.
It seemed OK so started moving the car a few yards back and forwards and the temp started going up to the top of the marked section, then eased a little.

Continued to run it and it started going right to the top of the marked section.
I am letting it cool down then will check the coolant level and see if it needs topping up.
You could see the level looked OK but it took quite a bit less to fill it up then came out when drained the radiator, so may have a air blockage somewhere.

Any ideas where the best place on the system to get rid of any air from the system.

Of course, when draining the system in the first place I forgot to undo the cap on the bottle first and on removing the radiator drain plug got drenched when it camout under pressure.

UPDATE: Just been to check the levels when it has cooled down again and it was around a third of the way up the bottle, so topped it up again and will retest it tomorrow.
Click to expand...

had a similar problem on a p38 I owned years ago.traced it to a faulty bcm which actually failed weeks later.temp would suddenly rise on dashboard into the red for no reason & no overheating.when guage was high I switched on lights + anything what loaded the electrics & it sent the guage instantly back to normal.
 
Druim said:
Did you follow the refill procedure in Rave? Doesn't sound like it, they can be tricky but once you know how, it's easy when done correctly.

Refill
8. Ensure sufficient coolant solution is available.
See LUBRICANTS, FLUIDS AND
CAPACITIES, Information.
9. Inspect radiator drain plug ’O’ ring, renew if
required.
10. Fit drain plug to radiator. Tighten to Max 6 Nm
(4 lbf.ft)
11. Remove safety stands. Lower vehicle.
12. Disconnect radiator bleed hose at the radiator.
13. Blow through hose to clear any residual coolant.
Reconnect hose.
CAUTION: If radiator bleed hose is not
cleared of coolant, air may become
trapped at top of radiator during refill,
leading to subsequent engine overheating.
14. Fill expansion tank until coolant is level with
base of neck.
15. Start engine, continue filling at expansion tank
until coolant level stabilises at the ’COLD
LEVEL’ marking.
16. Run the engine until the thermostat opens (top
hose becomes warm).
17. Stop engine, allow to cool.
18. Check coolant level, top-up as necessary.
19. Refit expansion tank filler cap.
Click to expand...


Well ye bugger!! Thank you Druim, it took quite a bit more coolant doing it this way and the temp gauge, once warmed up, sits just under half way on the middle marked section.

Bring back the old days of filling it up via a cap on top of the radiator. ;)

Funny thing was, I was going to recheck the pump timing again after changing it a short while ago as it was sluggish and puffs of black smoke when setting off. Just now the puffs of black smoke have gone and it is pulling away well (uphill) outside my house, maybe connected or maybe not?

Thanks for the advise Wammers and Druim.
 
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