Hi ive got a 1990 Audi coupe 2.3e B3 and ive opened the thermostat housing up so many times the 2 bolts holding it in place dont seem too good. Im worried incase i round them. Does anyone know where i could find some or have a part number? I know  i open them with a 10mm socket. Thanks Ian!

Hello Ian,

Sounds like they may be M6 bolts. Easiest and quickest route under our current situation is to look on EBay. You are likely to be spoiled for choice there. Beware, metric threads might have a number of different thread pitches for the same dia. but you can afford to go with the most popular variants and order a couple to compare. To check the treads are the same pitch, simply line up the new one tight against the old one. 

Some bolts used on vehicles have a flange of shouldered head so a washer isn’t required. This type should also be listed. 

Kind regards,

Gareth. 

Hi Gareth thanks for your help. I know now i need to to look for a m6 bolt with a 10mm head. I think i might know why my cars temperature keeps dropping while driving. I know the thermostat works and the thicker end goes nearest to the engine and the oring goes on between the thermostat and the housing. I think the problem might be that the thermostat is installed with the cross metal piece fitted horizontally from 9 to 3 o clock when it should be installed vertically from 12 to 6 o clock. I read an article saying this can cause an airlock behind the thermostat inside the engine block and can also cause problems with the cars heater. Im just waiting for a new oring to arrive then im going to change it and see what happens. Im hopeful this will work. I fitted the thermostat horizontally because the old one was fitted that way but the heater was never good then. Thanks for all the advice youve given me previously. Its been really helpful and much appreciated. Il let you know how i get on when i change the stat around. Thanks Ian!                                                                            The top image shows how the stat is installed at the moment and the bottom image shows how i think the stat should be fitted. Theres no air or bleed hole or arrow so i think it doesnt matter which way up it goes. Thanks again Ian!

Thanks Ian,

I don’t want to be pessimistic, but that’s a new one on me! Never heard the likes, but despite having more than a ‘few miles on the clock’, we are not too old to learn. 

Could you let us know how you get on Ian? 

Many thanks and kind regards,

Gareth.