Thermostat? Mk2 gti 8v (90's spec)

[mickysuperstar]

Hey guys...

I've searched around for my problem, but no-one seems to have my exact issue.

When my car is sat stationary, it gets up to the correct temperature, but when I start driving it drops down to zero!! If I'm sat in traffic, the temp starts to rise again!

It never overheats or shows any noticable performance issues... However, the lower radiator hose is quite hot - correct me if I'm wrong, but shouldn't the thermostat keep that cool?

I started to change the thermostat today, but got stumped by the pas pumps long bolt.. it just wouldn't budge! So didn't get the job done...

Anyone had either of these problems or have a solution?

Thanks!

[nealey]

Mine had the same problem, was the thermostat stuck open, the bottom hose is normally cold untill the thermostat opens but as yours is most likely stuck open the bottom hose will be hot once the cars up to temp.

Cant remember 100% how i tackled the pas pump but it was a bit of a nightmare doing it on my back in the dark, have you definately took all of the bolts out as some of them are well hidden

[jezza16v]

Hi, I had that bolt seized solid on my first 16v and the 8v I have now, seems to be designed to catch water in the slot and rust it in. I had to take the pump off by unbolting the front bracket from the front of the block and then there's a bracket underneath with a couple of bolts into the bottom of the block. Once I dropped the whole thing I managed to get that bolt free with a bit of heat, hammering and plus-gas. It will never rust in again now because I lubed it all up and then sealed it in with waxoyl!

[weazgti]

mine was like this and i found out i was missing a stat.

[mickysuperstar]

Yeah I want to change the thermostat before anything else coz it must be that!... Thanks for the advice  on the pas pump - I'll have to have another blast tomorrow.

My mate suggested my problem might be down to the temperature sender... Does that sound likely to anyone?

If I can't get the long bolt out from the pas pump, I'll try unbolting everything else until it loosens enough to drop! Nightmare though, why would they make it do difficult for pas models!? My mate has a 1987 mk2 and I changed his within 15mins!

[jezza16v]

Does not sound like the sender at all, be careful when you take the stat housing off, one nut is captive and tends to come out OK, the other is a through bolt and the back end of it rusts in, gentle & plus-gas, if it shears you'll have to take the pump off and drill it out, or worse in my case, get a new water pump!

[mickysuperstar]

I still haven't managed to get the long pas pump bolt removed... Arghhh!

I'm going to ask a mate to help tonight, but I need to make a 100 mile round trip this morning... Do you think it's safe to drive?

I'm thinking not... But if it's safe, I'll take her out!

[jezza16v]

Drop the whole pump unit then you will be able to free the bolt up.

[mickysuperstar]

Thanks a lot guys - got the pas to swing forward enough now!

The thetmostat had already been removed and was missing! 

I guess the cowboy who owned it before me did it, to hide the f**ked radiator issue... Now it has a new radiator and thermostat, she is running great...

Almost perfect, except for the ISCV! Grrr - next on the list!!

[weazgti]

sometimes people remove them when the headgasket is on its way out.