Am I just being a bit thick? 1.8T cooling system - Page 3

SD1too · 21st March 2013, 23:06

Quote:

Originally Posted by __chris__

Top hose is hot where it comes out of the engine across the T-Piece heading to the radiator.
Radiator however is still cold.
Bottom hose going into the stat is therefore cold.
Water in the expansion tank remains cold.
All despite the fact that the onboard diagnostics are telling me that the engine is reaching > 112 and the emergency fan is cutting in.

Those symptoms make me wonder whether a conventional thermostat is fitted and isn't opening.

Simon

kaiser · 22nd March 2013, 04:35

Quote:

Originally Posted by SD1too

Those symptoms make me wonder whether a conventional thermostat is fitted and isn't opening.

Simon

Worth a try. Should be a dummy, or nothing, but instead might be faulty extra thermostat.
See picture 32, black plastic housing near water pump (partly obscured).

http://www.the75andztclub.co.uk/foru...d.php?t=130997

vindaloo · 22nd March 2013, 08:50

Quote:

Originally Posted by E_T_V

Slow speed works on my 1.8T. Demist test doesn't work though as the aircon needs a refill.

Remember if the outside temperature is low the aircon will not engage.

kaiser · 22nd March 2013, 08:59

I have just tried my car with no gas in the A/C.
When the A/C is on, the fan comes on in the engine bay..

__chris__ · 22nd March 2013, 10:21

Quote:

Originally Posted by SD1too

Those symptoms make me wonder whether a conventional thermostat is fitted and isn't opening.

Simon

Had the same thought so had the mechanic check this last week while I was working from home. He dismantled the system and then showed me the 'dummy' thing that was there instead of a normal stat.

SD1too · 22nd March 2013, 12:39

When you refilled the cooling system, did you use the bleed screw as specified by MG Rover (and rerproduced in Haynes)?

Simon

__chris__ · 22nd March 2013, 14:37

Quote:

Originally Posted by SD1too

When you refilled the cooling system, did you use the bleed screw as specified by MG Rover (and rerproduced in Haynes)?

Simon

Yes Simon,

Up to a couple of weeks ago my bleed screw was just an 8mm bolt without the sealing washer. I then contacted seancar on here and bought one with the washer.

Following the steps in the Haynes manual, I removed the screw entirely and filled the expansion tank slowly keeping the level below the neck until a steady stream came out of the bleed screw hole. I then refitted the screw and started the engine keeping the revs at a fast idle until the water in the tank rose. I then replaced the pressure cap. Does this sound right to you?

T-Cut · 22nd March 2013, 16:03

Something worrying here.

Quote:

Originally Posted by __chris__

(testing stat in hot water) - - have just done this with the new one (which previously hadn't made any difference). After a while in the pot, the air bubbled out and the stat opened. Kept it in for a while, simmering away and it produced a decent amount of white wax in the water. Perhaps it had been sticking/reluctant to open before and now it's been "seasoned" I'm going to try and fit it tomorrow in the reassuring knowledge that it works.

Kaiser remarked on the wax loss, but the point was ignored. You refitted the stat because 'it works'.

Quote:

Removed the original PRT and boiled it up. Horrible looking inside but did actually open. Put the new one back on anyway as it looks cleaner and I know from yesterday that it too opens.

A stat that loses a 'decent amount of wax' won't afterwards open as it should. It will cause overheating, which is what you have. The new stat is faulty on the basis of your test.

Quote:

If I rev the car hard at start up when its sitting on the drive, then the stat will open and the radiator gets nice and hot, but otherwise despite having had the head skimmed and the MLS gasket fitted, flushed the system, and replaced the pump and stat, the temperature keeps heading up to 120 when I'm doing the school run.

Doing this without a correctly functioning radiator fan will cause temperature escalation.

Quote:

There was no warmth coming out of either the driver or passenger side heater, so I am wondering whether
a) The matrix is bunged up with something that is stopping circulation
b) The pump is not pushing the water round the system

Did the heater work before? Has the overheating problem started since having the head/gasket work done? If so, I'd want to know why?

I'd certainly refit the old PRT or get the faulty one replaced under warranty. Fix the fan. Ask the mechanic why there's now no flow through the heater matrix.

TC

__chris__ · 22nd March 2013, 16:39

Thanks TC.

Didn't want to ignore Kaiser's point about the wax, but I had been using the original PRT with all the problems, and thought to try the new one since I could see that it opened properly when boiled. There was also the point that new ones aren't usually faulty.

When I boiled up the original one I noticed a tiny amount of black plastic-like film in the water and the inside of the housing looks horrible so didn't really want to put that back on and so, from how I read it, your diagnosis is to get a replacement PRT??

Appreciate how important having the slow speed is and the Golden Resistor arrived today but it's freezing cold with sleet and I've not removed the bumper before so I may not get this done today. I know there's a how-to remove the bonnet on here somewhere so hope I can manage this.

I'm hoping then that if I get a working PRT and the resistor fitted that may be it.

Prior to having the head/gasket work done, I had had overheating / water loss issues due to leaking hoses and a broken t-piece but nothing like this.
I had these replaced. No problem with the heater then.

Took the car out for a reasonable run shortly afterwards, mix of dual carriageway / stuck in traffic jams. No problems that day.

Following weekend, slow traffic journey resulted in overheating and breakdown being called out to be safe (had small child in car).
Not been able to properly use the car since...

Please feel free to continue to add any other advice for me, I really do appreciate it.

Craig parker · 22nd March 2013, 23:59

Quote:

Originally Posted by vindaloo

Remember if the outside temperature is low the aircon will not engage.

The other morning at 05:30 and -2 degrees I pressed the demist button and my slow speed fan did not kick in, I heard no click of the condensor starting, my air con is fully gassed, is this because of the extreme cold weather then? Later in the day the fan and condensor kicked in straight away when demist was pressed?? Can someone explain why the system does this?? I thought my fan was goosed but its fine

Regards

Craig

22nd March 2013, 12:39	#26
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,385 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	When you refilled the cooling system, did you use the bleed screw as specified by MG Rover (and rerproduced in Haynes)? Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

22nd March 2013, 16:39	#29
__chris__ Avid contributor 2003 MG ZT 190+,(2005 Facelift R75 1.8T SE Conny now consigned to be a donor car) Join Date: Sep 2012 Location: Sidcup Posts: 149 Thanks: 34 Thanked 4 Times in 4 Posts	Thanks TC. Didn't want to ignore Kaiser's point about the wax, but I had been using the original PRT with all the problems, and thought to try the new one since I could see that it opened properly when boiled. There was also the point that new ones aren't usually faulty. When I boiled up the original one I noticed a tiny amount of black plastic-like film in the water and the inside of the housing looks horrible so didn't really want to put that back on and so, from how I read it, your diagnosis is to get a replacement PRT?? Appreciate how important having the slow speed is and the Golden Resistor arrived today but it's freezing cold with sleet and I've not removed the bumper before so I may not get this done today. I know there's a how-to remove the bonnet on here somewhere so hope I can manage this. I'm hoping then that if I get a working PRT and the resistor fitted that may be it. Prior to having the head/gasket work done, I had had overheating / water loss issues due to leaking hoses and a broken t-piece but nothing like this. I had these replaced. No problem with the heater then. Took the car out for a reasonable run shortly afterwards, mix of dual carriageway / stuck in traffic jams. No problems that day. Following weekend, slow traffic journey resulted in overheating and breakdown being called out to be safe (had small child in car). Not been able to properly use the car since... Please feel free to continue to add any other advice for me, I really do appreciate it. __________________ Chris. Work on the 1.8T New pads &cs all round, Bonnet Catch Reversed, Plenums Cleaned, Renewed Selected Radiator Hoses, New Stainless Steel Twin Exhaust,Metal T-Piece, Head Skimmed and MLS Head Gasket, New Cambelt & Alternator Belt, New PRT & Water Pump, New Air Duct Hose, New Radiator, New plugs, coil packs & HT leads, Golden Radiator Resistor. Car then blew up and I gave up. Bought the ZT 190 instead ! Last edited by __chris__; 25th March 2013 at 09:44..

22nd March 2013, 08:59	#24
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	I have just tried my car with no gas in the A/C. When the A/C is on, the fan comes on in the engine bay..