1.8 Turbo Thermostat

[gmax333]

I've been searching the forum however am getting a little confused as to where the thermostat is located. I currently have a '53 (Sep 2003) ZT 1.8T. The symptons I am having is that the engine takes an age to warm up (15 minutes) and at speed the engine actually cools down (below half way).

I have made the assumption that the Thermostat is faulty - would this be the right assumption? If so, where about is it located on this car. On cars I have had previously it is usually in the top hose at the front of the engine near the block

Help with location would be excellent.

cheers for your help

[chrissyboy]

I've been searching the forum however am getting a little confused as to where the thermostat is located. I currently have a '53 (Sep 2003) ZT 1.8T. The symptons I am having is that the engine takes an age to warm up (15 minutes) and at speed the engine actually cools down (below half way).

I have made the assumption that the Thermostat is faulty - would this be the right assumption? If so, where about is it located on this car. On cars I have had previously it is usually in the top hose at the front of the engine near the block

Help with location would be excellent.

cheers for your help

hope this is of help to you ...

[pab]

the best way to access to PRT (pressure relief thermostat) is to remove the under tray,the unit will be of of an opaque clear colour.

rimmers and xpart can supply these replacements and the colour is black,but i have been assured they are the same specification.

[gmax333]

Do all 75's/ZT use the same PRT or is this specific to the 1.8?

[Gman2]

As far as I'm aware the PRT is unique to the 1.8 (T)? It was fitted on late 03 plates onwards as one of the measures to reduce HGF. I've got the same problem on the ZTT and have one ordered from Rimmers. They've confirmed that although it's black it's the one for the job.

[gmax333]

How much is the PRT (it sounds like some form of pill lol).

[chrissyboy]

How much is the PRT (it sounds like some form of pill lol).

it does lol ,think my other half is suffering from that ...:D

here is the price from rimmers
http://www.rimmerbros.co.uk/Item--i-PEM101020

[dbdenia]

Hi All. I have just changed my 1.8T engine with an MG 1.8T second hand. 2003. The thermostat on the old and replacement engine was situated in a housing at the rear of the engine. My very experienced mechanic confidently said that the new replacement old type themostat will be OK, and to fit a PRT would require new plumbing hoses etc. So far I have done 500 miles and all seems OK. but I still drive in fear.
I do not want another HGF so should us 1.8T owners consider fitting a PRT thermostat mod? If so please advise what hoses etc are required. Also advise where the hoses can be obtained.

I live in Spain and obtaining parts here is almost impossible.

[T-Cut]

So not all 1.8 Turbos came with the PRT? I thought they did, but maybe it was introduced quickly following a rash of HGFs in this engine (??)

As noted elsewhere, the engines with the PRT still retain the original thermostat housing near the head. It contains a 'dummy' stat or orifice plate. It's a common mistake to fit a normal thermostat in there when a garage unfamiliar with the engine does HGF work. The two stat result is usually dramatic.

If you do some Google searches, you'll find lots of stuff about PRT conversion in the K-series, mainly in MGF/TF and Lotus Elise.

TC

[gmax333]

Ordered a PRT yesterday from Mushroom garage in Rotherham so I will give this a go on Monday. For anyone who lives in Yorkshire Evans Halshaw in Leeds have 4 of these in stock and Rimmer Brothers in Lincoln have 7.

I am hoping this cures the problem.

From memory OAT coolant is usually used in these engines however my car has blue coolant. Now I know the colour of the coolant does not always tell you what type of coolant it is, however is anyone able to make an educated guess what type of coolant I have fitted? Rover OAT is usally pink.

[T-Cut]

Blue antifreeze has a different formula from OAT (Red/Orange/Pink) and they must not be mixed. Either use blue stuff for topping up or do a drain and flush if you wish to use OAT. Blue stuff should be renewed every two years. OAT is now good for 4 - 5 years.

TC

[gmax333]

Does the 1.8T have a bleed nipple?

[chrissyboy]

Does the 1.8T have a bleed nipple?

yes ,you will find it on the thick hose between the bater and the engine,make sure that alll air is out the system what ever methord you use to bleed the system ...

[chrissyboy]

Hi All. I have just changed my 1.8T engine with an MG 1.8T second hand. 2003. The thermostat on the old and replacement engine was situated in a housing at the rear of the engine. My very experienced mechanic confidently said that the new replacement old type themostat will be OK, and to fit a PRT would require new plumbing hoses etc. So far I have done 500 miles and all seems OK. but I still drive in fear.
I do not want another HGF so should us 1.8T owners consider fitting a PRT thermostat mod? If so please advise what hoses etc are required. Also advise where the hoses can be obtained.

I live in Spain and obtaining parts here is almost impossible.
if the engine had a place or the statin it is a dummy one then that engine will require the prt type stat ... you just cant have 2 stats in one system ... all 1800 turbo`s from 2003 was fitted with these ...as the engine you have in the car is from a 2003 car i would use prt ,sounde like you have a 1800 engine fitted now but with the turbo it will bnned the prt .

[T-Cut]

if the engine had a place or the statin it is a dummy one then that engine will require the prt type stat ... you just cant have 2 stats in one system ... all 1800 turbo`s from 2003 was fitted with these ...as the engine you have in the car is from a 2003 car i would use prt ,sounde like you have a 1800 engine fitted now but with the turbo it will bnned the prt .

I wish I could understand this. Maybe you could type a little slower?

TC

[chrissyboy]

I wish I could understand this. Maybe you could type a little slower?

TC

sorry tc and others that have had a hard time understanding what i wrote ... is this clearer


if the engine you put in now had a plate, the stat in it is a dummy one. then that engine will require the prt type stat ... you just cant have 2 stats in one system ... all 1800 turbo`s from 2003 was fitted with these ...as the engine you have in the car is from a 2003 car i would use a prt ,sounde like you have a 1800 engine fitted now but with the turbo it will requiring the prt .

[gmax333]

From the excellent info about operating the Obd on instrument panel I managed to get the accurate temp. I noticed when in traffic that temp got to 112oC I don't know if it would have gone higher as I put heater on to get it to less than a hundred this propmted me tO ask what is the operating temp of the engine. On my passat it is 90oC with redline at 120oC. Surely fan should come in at the temp I was getting?

[chrissyboy]

From the excellent info about operating the Obd on instrument panel I managed to get the accurate temp. I noticed when in traffic that temp got to 112oC I don't know if it would have gone higher as I put heater on to get it to less than a hundred this propmted me tO ask what is the operating temp of the engine. On my passat it is 90oC with redline at 120oC. Surely fan should come in at the temp I was getting?


if you stopped in traffic and the temp rose o 112 ,did you hear the fan cut in ?the fan should cut in when the temp hits 104 and stay on till it lowers to around the 96 mark ..if the fan didnt come on then i think if you have a 3 speefan then its the brushes gone if you have a 2 speed fan then th resistor has failed .. to know which speed of fan you have look at the grill at front of ar . if you see a silver bit at the 2 o/clock postion then you have a 2 speed fan .if you dont see it then i is a 3 speed fan ... if a 2 speed fan you can oeder a uprated resistor from jules ,they are easy to change .. jules also sells a 2 speed kenlowe fan and supplies good fitting instructions . how is the coolant level ... also does the fan run when you park up and turn off the engine and sound like a hover craft? you ca start car press the demist button on the dash and then look through the grill to see if the fan is running . if it is then the fan is working , if not you need to find out why it isnt working ...also member gerry3 sells an uprated metal te piece that he makes which is very well made and is a good idea to replace the plastic one for this metal one as it will never go out of shape due to the heat these engines can reach there is also a good and detailed post by tc on the fan and the when it should cut in

[vindaloo]

From the excellent info about operating the Obd on instrument panel I managed to get the accurate temp. I noticed when in traffic that temp got to 112oC I don't know if it would have gone higher as I put heater on to get it to less than a hundred this propmted me tO ask what is the operating temp of the engine. On my passat it is 90oC with redline at 120oC. Surely fan should come in at the temp I was getting?

Something is not right, you shouldn't be reaching 112C in this weather, as has been said the low speed fan will cut in at 104C and back out again at 96C. My late pre-facelift Jan04 1.8T has a 2 speed fan without resistor (2-pole motor?), according to Jules this is correct for a 1.8T.

BTW the member who sells the metal T-piece is gerry3 NOT jeey3.

[gmax333]

The gauge on the dash stayed at halfway oddly. It has been 15oC here ambient. I am supprised it went this high. I heard no fan. Coolant is midway between min and max. Prt doesn't work.

[vindaloo]

The gauge on the dash stayed at halfway oddly. It has been 15oC here ambient. I am supprised it went this high. I heard no fan. Coolant is midway between min and max. Prt doesn't work.

The gauge is useless, if it goes above halfway it's probably too late. If you've no fan at 112C I'd be getting it checked out before I drove it again.

[chrissyboy]

Something is not right, you shouldn't be reaching 112C in this weather, as has been said the low speed fan will cut in at 104C and back out again at 96C. My late pre-facelift Jan04 1.8T has a 2 speed fan without resistor (2-pole motor?), according to Jules this is correct for a 1.8T.

BTW the member who sells the metal T-piece is gerry3 NOT jeey3.


typo corrected;)

[T-Cut]

My late pre-facelift Jan04 1.8T has a 2 speed fan without resistor (2-pole motor?), according to Jules this is correct for a 1.8T.


That's interesting. I thought all 2-speed motors had the slow speed resistor. That particular type must have been fitted to very few cars.

TC

[vindaloo]

That's interesting. I thought all 2-speed motors had the slow speed resistor. That particular type must have been fitted to very few cars.

TC

I was a bit surprised as it never seems to get a mention anywhere. I got the impression from Jules that most 1.8T's are fitted with this type but I could be wrong, perhaps Jules might like to step in?

[T-Cut]

No, the vast majority of 2-speed systems (incl. the 1.8turbo) have the resistor controlled slow speed. I can't understand why they changed from a true 2-speed motor (like yours) to a single speed type and a voltage reducing resistor.

TC

[vindaloo]

My car was built in Jan2004. Are the resistor ones earlier or later?

[T-Cut]

The resistors are only fitted to the later 2-speed motors. They were introduced during the facelifting period but late Mk1s may have 2-speed and early Mk2s can have 3-speed. The original 3-speed system uses a multi-brush circuit arrangement within the motor. This causes rapid wear of the slow speed brush and why so many people swap them for the OEM 2-speed or the Kenlowe.
Your resistor-less 2-speed is a rarety if that is what you have.

TC

[vindaloo]

.....
Your resistor-less 2-speed is a rarety if that is what you have.

TC

Yes, according to Jules that's what I have. You don't get a pre-facelift manufactured much later than Jan04 so I'm surprised I don't have the 2 speed with resistor. May be a blessing, maybe not. Don't know how good the non-resistor type motor is.
Interested to know how many 2 speed non-resistor types are around?

[chrissyboy]

dont some 2 speed fans have the resistor on the back of cowling so you cant see it through the grill..my car is a late 03 model and has the 2 speed fan .which has the resistor, now i dont know if it was fitted from new or a previous owner had it fitted ,,maybe someone fitted the one you have in your car as i cant find anything about it anywhere .

[vindaloo]

dont some 2 speed fans have the resistor on the back of cowling so you cant see it through the grill..my car is a late 03 model and has the 2 speed fan .which has the resistor, now i dont know if it was fitted from new or a previous owner had it fitted ,,maybe someone fitted the one you have in your car as i cant find anything about it anywhere .

Definitely the original fan, car only has 12k miles from new & according to Jules definitely no resistor

[T-Cut]

Oh! hang on a bit. The 1.8s do indeed have 2-speed fans, both Mk1 and MK2 models. I am always the V6 mindset when discussing fans. The 1.8s had a smaller 2-speed motor without resistor on the earlier system. This became the 2-speed with resistor during facelifting. Sorry to confuse the issue, I should know better by now.

TC

[chrissyboy]

Oh! hang on a bit. The 1.8s do indeed have 2-speed fans, both Mk1 and MK2 models. I am always the V6 mindset when discussing fans. The 1.8s had a smaller 2-speed motor without resistor on the earlier system. This became the 2-speed with resistor during facelifting. Sorry to confuse the issue, I should know better by now.

TC

can i ask something .. my car is mk 1 and has the 2 speed fan with resistor .. so was my 2 speed fan fitted as standard or do i have a fan that was fitted by a previous owner,as you say the 2 speed with resistor as fitted on during the face lifting:confused:

[dbdenia]

Back to square one. The original question was about thermostats. My original 1.8 T engine definitely did not have a PRT. the car was registered in March 2003.

[T-Cut]

can i ask something .. my car is mk 1 and has the 2 speed fan with resistor .. so was my 2 speed fan fitted as standard or do i have a fan that was fitted by a previous owner,as you say the 2 speed with resistor as fitted on during the face lifting:confused:

Since your car is registered 2003 then it's probably the original. The earlier 2-speeders may well have had a service life of 50-60K miles like the 3-speeders, but I haven't read about that particular situation. It will depend on your mileage for a better idea.

TC

[T-Cut]

Back to square one. The original question was about thermostats. My original 1.8 T engine definitely did not have a PRT. The car was registered in March 2003.

That tallies with what is known. It was probably made shortly before the introduction of the PRT.

TC

[chrissyboy]

Since your car is registered 2003 then it's probably the original. The earlier 2-speeders may well have had a service life of 50-60K miles like the 3-speeders, but I haven't read about that particular situation. It will depend on your mileage for a better idea.

TC


registered in august 2003 and has done 70,000 miles..fan is still working great last year changed the resistor .. fo one of juyles golden ones

[dbdenia]

That tallies with what is known. It was probably made shortly before the introduction of the PRT.

TC

The cooling system layout of a Rover 75 1.8 turbo without a prt fitted should look like this: Click (http://www.the75andztclub.co.uk/forum/imagehosting/127884d31db016d27a.jpg)
Thank you for this. It confirms that the early 1.8 T's did not have PRT. I began to think that a previous owner had made some alterations.

[gmax333]

Is there anyway to tell if my fan is 2speed with resistor or 2speed stepped motor?

Sounds like I am best off replacing the fan to a Kenlowe ones, what is the rough cost of this unit?

Cheers everyone

[Thomas]

Is there anyway to tell if my fan is 2speed with resistor or 2speed stepped motor?

Sounds like I am best off replacing the fan to a Kenlowe ones, what is the rough cost of this unit?

Cheers everyone


Send a pm to Jules he is an expert with cooling fans and can supply you a kenlowe etc amongst other things!