300tdi thermo housing gasket

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discomania

Well-Known Member
Posts
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Before I take this apart, is the themorstat housing gasket of the cardboard type or what?

Got the thermostat today, although they didn't have a gasket, they suggested using a piece of cardboard, but I am not going to strip it until I know for sure.

Also, according to my holts anti freeze, 25% will protect against freezing and is the IDEAL mix for summer cooling, but I am going to put in about 50% as I want more than just freeze protected. Not being too up on coolant science, I wonder if this higher concentration is going to have an effect when it comes to cooling in the summer?
 
300tdi thermo changed; and now I have a blast furnace heater and hot engine! I hadn't realised how good the Discos heating was!

Put the old one into some hot water, opened at about 80something ish, and has still not closed even after being taken out the water and let sit for hours!

See those little plastic caps for the fillers, whos forking idea was it to make them like that, there a pain in the arse.
 
hi discomania,just visited the site after a long absence & saw your article. It rings a bell with me as my temp is nothing like it was before i changed my water pump a month ago. high concentration antifreeze applied & all bleed tricks in the book used.Mine is a 1994 300tdi auto,188k.Mind telling me cost & time to do? is it like the old waxstats of days gone by?thanks a lot.muck`un
 
Get rid of those plastic plugs quick, before they blow out and cook your engine! I thought everyone with a 300tdi had brass plugs fitted. You should be able to get them from a plumber's supply place, as they are a standard BSP thread.

ps. The 300tdi thermostat does not have a gasket - the sealing is done by the rubber ring.
 
the rubber ring only seals the thermostat into the groove where it sits to stop water flowing from one side to the other, the gasket seals the housing to the block to form a watertight joint between both. wwithout a gasket the water would seep out of the housing where it joins the block
 
There is a gasket between the thermostat housing and the block, true, but I have managed all these years without a gasket (or RTV etc) on the housing itself. There was not one fitted originally, and is not now. But if it did leak I would use some RTV on it. I reckon it depends on how well the rubber seal works. I do put copper grease on the two bolts so that they will be removable in the future, though. (always a problem with steel bolts in alloy castings, as we all know). :(
 
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