Diesel thermostat definative answer - Page 71

RichB · 28th December 2010, 16:06

I've seen some peculiar results with my 88Deg Renault stat. I see the temp rise steadily up to about 94 or 95 then plummet down to 82 or 83 and slowly build up. It does this two or three times but then after that it sits at 83 or 84 deg which is exactly the same as I was getting on the stock stat. It's like the renault one stays open a bit after it has cycled a few times. Or maybe it is getting heatsoaked? I've had the same result on two 300 miles journeys recently so I'm concluding the renault stat is no good (for me).

I do have the specialist components stat to go on, think I will give that a try with the 92 deg stat fitted.

Cheers,
Rich

T-Cut · 28th December 2010, 18:41

Whatever a stat is rated at, it's approximate. One stat rated as 92C may perform like another rated at 88C. Even if they open at exactly the rated temperature, the car's radiator is so effective, they will all show a temperature drop as they open. I'm beginning to get the impression that unless some modification is made to the radiator side, no significant change from the results reported thus far will be seen. Nobody will be running at the optimal 95-100C without modifying the radiator/cooling efficiency. It needs a venetian blind type set up on the radiator face.

TC

RichB · 28th December 2010, 19:36

I'm running with a sheet of cardboard blocking the top 70% of the rad. Last year when I was playing about with this, I only noticed a slight difference when the whole radiator was blocked, but I removed the last 30% when summer arrived this year. Maybe I need to re-instate that piece.

Rich

wuzerk · 28th December 2010, 20:13

RICH B: if you are using the later radiator fan with the large resistor then you stand a good chance of burning it out if it is in the blanked off area.

RUSS: your 'stat seems to give a rather wide range of temperatures, wouldn't expect to see readings in the 70 s once it has warmed up.
Perhaps it is just that particular one? It seems reluctant to close.

BigRuss · 28th December 2010, 20:40

Going to give the car a lot longer run tomorrow if possible, the car did warm up faster up to 75 degrees, but slowed considerably after that. I was disappointed with the results especially the temp of the top hose.

The Renault stat I'm using is a different type than the one Jules used, it may be that it needs to be pushed further into the top hose, as it may be too near the heater take off in the stub, either that or the stat may need a small relief hole drilling to get some flow over the wax cartridge when the stat is closed.

Russ

wuzerk · 28th December 2010, 20:48

RUSS: If there was any sort of air lock preventing flow to the wax cylinder it would disappear after the first opening and yours seems to have opened(96C) and, if it hadn't, the temperature would have kept climbing.

BigRuss · 28th December 2010, 23:25

Quote:

Originally Posted by wuzerk

RUSS: If there was any sort of air lock preventing flow to the wax cylinder it would disappear after the first opening and yours seems to have opened(96C) and, if it hadn't, the temperature would have kept climbing.

There's no air lock, made sure it was bled after I fitted the stat (the Gates stat was very easy to fit with no cutting of the stat necessary, no top up or draining required).

It's very much a work in progress and it may take a little fine tuning of the stat's position etc to see if it makes a difference if tomorrows run still gives poor results.

Russ

RichB · 29th December 2010, 09:47

Quote:

Originally Posted by wuzerk

RICH B: if you are using the later radiator fan with the large resistor then you stand a good chance of burning it out if it is in the blanked off area.

I have the earlier radiator fan. And the temps have never got up enough for it to kick in automatically. I watched the temp like a hawk last summer and only once saw temps creep into 100's and it dropped as soon as I switched the aircon on.

Rich

ardvark · 29th December 2010, 10:26

71 PAGES! That'll take ages to digest. Can anyone of you fill me in what the end result is please? So I can keep up with any future content.

T-Cut · 29th December 2010, 10:30

Quote:

Originally Posted by ardvark

Can anyone of you fill me in what the end result is please?

There isn't one yet. You'll just have to keep up I'm afraid.

TC

28th December 2010, 16:06	#701
RichB Gets stuck in ZT260 SE, ZT-T+ CDTi Join Date: Aug 2009 Location: Staffs Posts: 583 Thanks: 13 Thanked 16 Times in 13 Posts	I've seen some peculiar results with my 88Deg Renault stat. I see the temp rise steadily up to about 94 or 95 then plummet down to 82 or 83 and slowly build up. It does this two or three times but then after that it sits at 83 or 84 deg which is exactly the same as I was getting on the stock stat. It's like the renault one stays open a bit after it has cycled a few times. Or maybe it is getting heatsoaked? I've had the same result on two 300 miles journeys recently so I'm concluding the renault stat is no good (for me). I do have the specialist components stat to go on, think I will give that a try with the 92 deg stat fitted. Cheers, Rich __________________ 53 MG ZT 260 SE Monogram Garnet Red #073 61 Seat Exeo ST TDI Daily Driver 99 Mazda MX-5 Turbo tracktoy

28th December 2010, 19:36	#703
RichB Gets stuck in ZT260 SE, ZT-T+ CDTi Join Date: Aug 2009 Location: Staffs Posts: 583 Thanks: 13 Thanked 16 Times in 13 Posts	I'm running with a sheet of cardboard blocking the top 70% of the rad. Last year when I was playing about with this, I only noticed a slight difference when the whole radiator was blocked, but I removed the last 30% when summer arrived this year. Maybe I need to re-instate that piece. Rich __________________ 53 MG ZT 260 SE Monogram Garnet Red #073 61 Seat Exeo ST TDI Daily Driver 99 Mazda MX-5 Turbo tracktoy

28th December 2010, 20:13	#704
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	Radiator blanking RICH B: if you are using the later radiator fan with the large resistor then you stand a good chance of burning it out if it is in the blanked off area. RUSS: your 'stat seems to give a rather wide range of temperatures, wouldn't expect to see readings in the 70 s once it has warmed up. Perhaps it is just that particular one? It seems reluctant to close. Last edited by wuzerk; 28th December 2010 at 20:21..

28th December 2010, 20:40	#705
BigRuss Premium Trader 75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4) Join Date: Jul 2007 Location: Liversedge, West Yorkshire Posts: 5,416 Thanks: 1,105 Thanked 1,340 Times in 661 Posts	Going to give the car a lot longer run tomorrow if possible, the car did warm up faster up to 75 degrees, but slowed considerably after that. I was disappointed with the results especially the temp of the top hose. The Renault stat I'm using is a different type than the one Jules used, it may be that it needs to be pushed further into the top hose, as it may be too near the heater take off in the stub, either that or the stat may need a small relief hole drilling to get some flow over the wax cartridge when the stat is closed. Russ __________________ Replacement Key Service http://https://the75andztclub.co.uk/...d.php?t=244732 Full T4 Testbook diagnostics available. Diesel ECU repair and replacement. Options enabled or disabled as required. Diesel X-Power 135 and "160", Rover 1.8T 150 to 160 MG 160 V6 to 177 upgrades available P.M. for details.

28th December 2010, 20:48	#706
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	Stat RUSS: If there was any sort of air lock preventing flow to the wax cylinder it would disappear after the first opening and yours seems to have opened(96C) and, if it hadn't, the temperature would have kept climbing. Last edited by wuzerk; 28th December 2010 at 20:56..

28th December 2010, 18:41	#702
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	Whatever a stat is rated at, it's approximate. One stat rated as 92C may perform like another rated at 88C. Even if they open at exactly the rated temperature, the car's radiator is so effective, they will all show a temperature drop as they open. I'm beginning to get the impression that unless some modification is made to the radiator side, no significant change from the results reported thus far will be seen. Nobody will be running at the optimal 95-100C without modifying the radiator/cooling efficiency. It needs a venetian blind type set up on the radiator face. TC

29th December 2010, 10:26	#709
ardvark Al 75 CDTI Tourer Auto Join Date: Mar 2009 Location: Studley Posts: 1,457 Thanks: 1 Thanked 69 Times in 48 Posts	71 PAGES! That'll take ages to digest. Can anyone of you fill me in what the end result is please? So I can keep up with any future content. __________________ ARDVARK