overheating and no hot air....

[kentyboy 0]

help!!!! have had a good look through forum and cannot find a straight answer...have a 1.8 kr 1990,scene of events are as follows,had a little leak of oil from the oil cooler,removed the water pipe from the side,removed the oil filter,replaced the seal from between the two blocks. put a new oil filter in,topped the oil up and the water as lost some from removal of the pipe..now have engine overheating and no hot air in cabin....was running fine before this,heater pipes are hot going in and cold coming out!! could there be an airlock,if so how to release it....can anybody help?

[eugopnosaj 0]

Is it losing water? A common sign of a matrix problem or water leak is no hot air (as theres no water running through the matrix)

[kentyboy 0]

no not losing any water,just getting very hot with no hot air in the heating,was fine before i changed the oil seal.....

[KipVR 1]

It's probably an air lock, squeeze the pipes a bit.

[weetos 0]

check your o-ring on the expansion cap, can cause a pressure lock if not sitting right

[kentyboy 0]

tried the squeezy thing,and expansion cap looks ok.......it appears to be in the heater pipes,one is hot the other is cold.....

[big ben 10]

does sound like you have air in the system to me

[weetos 0]

blocked matrix? stick a hose pipe in the hot one and see if water comes out of other outlet

[kentyboy 0]

just removed the inlet and outlet pipes to heater system,blew down the inlet pipe,and a load of water and air came out,re filled system and ran up,still getting very hot,the top rad hose is now swelling up,would a shot thermostat give these symptoms or not,am i right in thinking it is on the bottom of the water pump?

[Erny 0]

don't wanna sound like I'm tellin me granny to suck eggs, from past experiance I've gone with these, When your running you engine up to temp do you have your heaters on hot? Hot is open an free flowing help remove air etc. If the pipe is swelling an over geting then your engine is presurising, do you have one way valves into and out of the heater matrix? If so try running the car with out them get a bit of copper pipe in should help rule out faulty valve, as mentioned above header tank caps cause pressurising when they fail. run the engine up to temp with the header tank cap off and the heaters on let it bubble over and wait till the fan kicks in squezzing the pipes doesn't hurt, keep an eye on the water level, an let it cool also with the cap off, this should help clear the airlock.

Is your water pump working? Test your thermostat with a pan of hot water and a thermomiter so you know it's opening at the right temps.

[kentyboy 0]

right.....next steps are,new header tank cap,or does anybody know when you buy a new tank if you get the cap as well? then thermostat....i figured that the water pump is working because of the pressuring up..also have now discovered a pin hole in the top hose onto oil cooler.......

[Erny 0]

Have u ran it up to temp and let it cool with out your header tank cap on, as I said before that's a kinda safe way of getting airlocks out, valvers can be difficult to get em

outta,

a walk round your local scrappy or ask a mate if you can borrow there header tank cap to check, it seems to be more of a 8v fault for some strange reason but it's a cheap easy/free thing to rule out,

worst case scenerio you've blown your headgasket by fixing something, weird.

[kentyboy 0]

question? if i am not losing any water,and have no water in my oil or oil in my water,could it still be the head gasket?......really weird...purchased a new header tank and cap,also a new stat this morning,shall try these first...

[kentyboy 0]

well that didnt work....new header tank and cap,new thermostat......trying the water pump next....really odd,top and bottom hoses are getting hot,now the cooling fan has stopped cutting in,the hose end of the radiator is getting proper hot,but the other end is warm enough to keep your hand on,top and bottom,where the fan sensor is...can the radiator be blocked and still get top and bottom hoses hot?.....and why is it still pressuring up........

[carrots 1]

i had the same prob with my 1.8 16v,i changed the hoses,waterpump,thermostat,expansion tank,cap.turned out the rad was part blocked

[KIPVW 0]

hi mate, i'm having exactly the same problem as you after changing to a new expansion tank and flushing the system and replacing with nice new coolant, i have now poured through 25 litres and it is still crap.

 

I have a skoda garage 100 yards from work and the mechanic i know personally who works there is adamant it will need to be pressure bled with the gizmo they have at work so hopefully on weds or thurs eve mine will be sorted as he is going to loan the bleeding kit from work and do it at his house.

 

I'll let you know how i get on, good luck with yours too as i know exactly how it is :brickwall:

[kentyboy 0]

same as....have a friend that owns a garage,who also has one of those snap-on gizmos....works off compressed air....brilliant piece of kit...got rid of the air but still pressuring up..

[kentyboy 0]

right....really weird one,left the car overheating last night...started it up today,no more overheating,fan cutting in and out as per normal...great....but....no heating,both pipes in and out appear to be hot but still blowing cold air???????

[dannyboy 0]

try replace the valve on the heater pipes with copper pipe as said. mine was acting up,now ive got full heat,ready for a cold winter!

 

if it works try replace the valve as its a failsafe device if heater matrix blows through system overpressurizing

dont know if they have this part anymore

[davidwort 0]

when the stat opens at 80 degrees ish the bottom radiator hose should get warm pretty quick as the water flows through the rad at this point, up to then the hose will stay fairly cold. If there's no sudden warming of the bottom hose at the correct temp then you may well have a radiator problem.

[Supercharged 2]

This sounds very much like a stuck bypass valve for the matrix if fitted.

[kentyboy 0]

ok!!!!! we now have hot water going into the matrix...and the pipe is hot as far as the little black valve on the out pipe....suspect valve? has a little warm air now coming out of the blowers,then goes cold after a short while...what size copper pipe do i need? or will the plastic type water pipes suffice? oh...to note,the small link hose between the two valves is not getting very hot...should it or not?

[kentyboy 0]

yeeeeha!!! replaced the two valves with pipe....toasty warm now,does anybody know if they are available anymore,failing that its a trip to stevens vw dismantlers...

[SamG40 0]

I replaced my heater matrix at the weekend (what an arse of a job as everyone says) and when I filled up the system again I had this exact same thing. The pipes going in and out were cold but the valve was hot (Im assuming thats the big part of the pipe before the matrix?). I just kept massaging the pipe (ooer) with the engine running and a small section at a time it got hot towards the matrix. After it got through to the matrix it fed through ok and both in and out pipes got hot.