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mgf
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hi everyone

i have had intermittant overheating issues on my mgf mark 2 1.8 mpi since i bought it last august, i have another thread open on this. Anyway i purchased a second hang prt system from a mg tf and was reading about installing it which doesnt seem to be a big job. one thing i have read is other owners have said you need an copper restrictor ring to put in the old redundant thermostat housing next to water pump when you remove the thermostat. i cannot see where to purchase one of these so does anyone have an idea where i can get one assuming i definately need it?

thanks
martin
 

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mg_tf
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Hi,

I bought an MG TF a few years ago primarily as a project car. One thing led to another and it ended up being a compete rebuild. I would add that i have thoroughly enjoyed the project, so far!

One of the areas that i thought i would address was the cooling system. There was nothing wrong with the system when i bought the car but it was an opportunity to try and improve and avoid future issues. My car is a 2002 model so pre PRT thermostat. After much research I decided to opt for a remote thermostat. There is a lot of information about why the location of the thermostat in the K series can lead to head gasket failure. It should also be said that a well maintained cooling system is important to avoid an HGF. Long story short, i relocated the thermostat housing to the front of the car, just behind the radiator and installed an 83degC thermostat. By relocating the thermostat to the front i have increased the volume of water circulating around the engine ahead of the thetmostat. What this means is that it takes slighly longer for that volume of water to get up to temp, but that is offset by the 83degC thermostat, but crucially when the thermostat does open there is no in rush of cold coolant into the head resulting in a thermal shock to the head. I also fitted the MLS gasket and uprated oil ladder.

I removed the original thermostat from the existing housing and this is now open. I did not fit a restrictor to the housing, all that was required was a new seal for the now open housing.

So far i have had no issues with the car, it gets up to temp very quickly, although i do not use it during the winter months and coolant temp is rock steady during very hot days and after long drives.
 

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'06 MG ZR +120 (HQM) '04 MG ZR 105 (IAB)
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......There is a lot of information about why the location of the thermostat in the K series can lead to head gasket failure.....
...and a significant proportion of it is total cobblers ;)

The simple truth is that MG Rover started fitting a remote PRT to the TF and Rover 75/MG ZT in 2003, but there did not seem to be any noticeable decrease in the incidence of HGF on these later cars when compared with those not fitted with the PRT.

The very best thing to do to reduce the possibility of HGF is to open out the coolant passage openings in the head casting, and fit the SAIC 6-layer MLS gasket.

I don't know about obtaining the restrictor ring for the original thermostat housing on its own, but the complete thermostat housing for the later cars (which includes the restrictor) can be obtained from any XPart reseller under part number PEM000020.
 

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mg_tf
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Appreciate the comment, Man in the car, however i can only relay my own experience with the vehicles i have owned and still own. I do take your point regarding the incident level prior to and after PRT and was the reason i did not opt for that solution. In my opinion the volume of water circulating in that circuit prior to the PRT opening was not significant more than in the pre PRT circuit and would still result in a thermal shock to the head.

I would also add that I fitted Stainless Dowels in place of the plastic dowels in a further attempt to eliminate movement of the head during thermal cycling.
 

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Appreciate the comment, Man in the car, however i can only relay my own experience with the vehicles i have owned and still own. I do take your point regarding the incident level prior to and after PRT and was the reason i did not opt for that solution. In my opinion the volume of water circulating in that circuit prior to the PRT opening was not significant more than in the pre PRT circuit and would still result in a thermal shock to the head.

I would also add that I fitted Stainless Dowels in place of the plastic dowels in a further attempt to eliminate movement of the head during thermal cycling.
The accepted way is to remove the centre of the old thermostat and refit the outer part
 

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Cheers everyone. I will do what David suggests and remove the coil spring and just leave the outer ring.

thanks
martin
 

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mg_tf
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hi everyone

i have had intermittant overheating issues on my mgf mark 2 1.8 mpi since i bought it last august, i have another thread open on this. Anyway i purchased a second hang prt system from a mg tf and was reading about installing it which doesnt seem to be a big job. one thing i have read is other owners have said you need an copper restrictor ring to put in the old redundant thermostat housing next to water pump when you remove the thermostat. i cannot see where to purchase one of these so does anyone have an idea where i can get one assuming i definately need it?

thanks
martin
I just knocked out the centre of the old thermostat no problems since. I did fit a digital temperature gauge in the coolant supply hose near the radiator to monitor the temp and keep an eye on the radiator fan operation.
 
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