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Hi All,

Got a bit of a problem with my Mk1 Polo 1100cc. It’s overheating!
I’ve checked all the usual stuff and I suspected the thermostat since the car runs fine until it’s warmed up, when I would expect the thermostat to open. The radiator and expansion tank never actually get warm, but the rest of the hoses (and the block) get very warm indeed!

I tool the thermostat out and tested it in a pan of water, it opens around 85 degrees and then fully opens about 90 – 100 degrees so that looks okay. It was all bunged up with rusty cr@p in the housing though so I’ve cleaned it out. Does the thermostat only go back in one way as mine will fit either way and looks like it’d work the same either way around?

Anyway – anyone got any ideas? The radiator isn’t blocked and I’ve flushed the system – I still suspect the thermostat or perhaps the expansion tank cap although the seal in there looks fine.

Help!

Cheers

Stu

Stu wrote:Hi All,

Got a bit of a problem with my Mk1 Polo 1100cc. It’s overheating!
I’ve checked all the usual stuff and I suspected the thermostat since the car runs fine until it’s warmed up, when I would expect the thermostat to open. The radiator and expansion tank never actually get warm, but the rest of the hoses (and the block) get very warm indeed!

I tool the thermostat out and tested it in a pan of water, it opens around 85 degrees and then fully opens about 90 – 100 degrees so that looks okay. It was all bunged up with rusty cr@p in the housing though so I’ve cleaned it out. Does the thermostat only go back in one way as mine will fit either way and looks like it’d work the same either way around?

Anyway – anyone got any ideas? The radiator isn’t blocked and I’ve flushed the system – I still suspect the thermostat or perhaps the expansion tank cap although the seal in there looks fine.

Help!

Cheers

Stu

Hi Stu,

i did it every time in the same way.....

Clean the hole water system with fresh water. All the brown water has to be removed. If you need your MK 1 also in Winter, install a new
thermostat, opening at 82 or 85 degrees. If its a summer car, don't install an new one.
All our member with summer cars throw out the thermostat.

Check also the expansion tank's cap. Flush also the ex. tank and the complete cooler .

After refilling the system don't forget to open the little white scew at the heating system ( under the wipers - we call it WASSERKASTEN and WÄRMETAUSCHER) to get all the air out of the system.

Best regards

Mike

audi50 wrote: Hi Stu,

i did it every time in the same way.....

Clean the hole water system with fresh water. All the brown water has to be removed. If you need your MK 1 also in Winter, install a new
thermostat, opening at 82 or 85 degrees. If its a summer car, don't install an new one.
All our member with summer cars throw out the thermostat.

Check also the expansion tank's cap. Flush also the ex. tank and the complete cooler .

After refilling the system don't forget to open the little white scew at the heating system ( under the wipers - we call it WASSERKASTEN and WÄRMETAUSCHER) to get all the air out of the system.

Best regards

Mike

Thanks for the info Mike - didn't know about an air-bleeding screw under the wipers, will have a look for that. Going to have a go at sorting it out later - will let you know how I get on and post some pics of the Polo once it's on the road!

I do need the thermostat as I intend to run the car in the winter but I'm going to put it all back together without the thermostat for now just to test that the system isn't blocked somewhere. If it's ok then I'll fit a new thermostat.

Thanks again

Stu

Thanks for the help, I've tracked it down to a dodgy thermostat - running ok without one for now while I find a new one.

Stu wrote:Thanks for the help, I've tracked it down to a dodgy thermostat - running ok without one for now while I find a new one.

That's what I told......I'm glad that your MK 1 is running again.

Don't hesitate to ask the next time.

Best regards

Mike

New thermostat installed last night, runs fine again now - cheers again Mike! I will post some pics up once I get the car cleaned up, next week hopefully.

As a quick Hijack of your thread:

Stu!

I love your car!

It could be my imagination, but it looks absolutely mint!

Speedlaw wrote:As a quick Hijack of your thread:

Stu!

I love your car!

It could be my imagination, but it looks absolutely mint!

Cheers!

Have a look in the members cars bit, few pics in there if you haven't seen them already?

http://www.tigerstyle.co.uk/poloforum/v ... php?t=2352

It's not quite mint, few rusty bits around the bottom of the rear wheelarches but apart from that it's great and the interior is as new really. 53k miles in 23 yrs... just run in!

Yep - seen the pics.

Excellent find Stu!

I second Speedy's comments... Looks lovely mate!

Thanks for the positive comments about the Mk1, hopefully be at a few shows with it next season!