[ERIKSEN K]

Ok I can’t find a fix!!!! As some of you know I am a master ase tech. I have a 2000 gl, 2001 gls and now a 2003 turbo s. I just got the turbo s as my ex wife took the 2001. So here it is I replaced the t-belt water pump and t stat, all parts are from VW as pm the last owner did not know what had been done there was stop leak looked like bars copper in the coolant, when it was apart I flushed the rad, heater core, block, all hoses and coolant bottle I drove the car for a week no problems it had low heat but not bad. It over heated on the way to the e-test I got back home replaced the cap would not hold pressure heater was not working I figured that it needed to burp no such luck I pulled the heater core hoses off flushed the core got new coolant from VW re flushed the system used my coolant vac gage to pull the air out refilled the system. I had no heat and almost over heated and lower rad hose was cold so warranted the t-stat, This still has not fixed the problem I have no heat intermittently when there is no heat both heater hoses are cold vech is not over heating it does not matter if I am driving or on idle it comes and goes fans come on it has a new fan module and ect from VW I did do a co2 test and cly leak down test there the system holds pressure and will hold a vacuum so there is no head gasket leak the vech seams like its low or no flow, I did replace the pump it is the steel one under warrantee re flushed the heater core, rad, and block theirs is flow and no sigh of stop leak and still the heat comes and goes. I have conceder replacing the heater core at this point. Has anyone had this problem?
Thank you all for your time on this one.

 

[02SilverSport]

Wish I had an answer for you - someone will hopefully provide some insight for you soon!


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[2004NBTURBOS]

Not a tech here, but if that stop leak rabbit turd stuff was put in, my first guess is that it has maybe clogged the radiator. I have seen that stuff destroy radiators. Not sure if that is the problem or not. Found this while checking out CraigsList VW Volkswagen Audi Mk4 1.8T radiator Brand New

After re-reading your post I have a quick question. Is the car still over heating? If no, and the only problem is the heat kicking on and off, I am guessing it is the "blend door". A little flapper door that regulates how much heat is coming out. Now this is all a guess, but you may have a vacuum leak that is kicking the door open or closed. Thats if they are vacuum controlled or cable. Thats it.......sorry.

 

[IggysMom]

I'm no expert either, but I know the radiators were a problem on these. I know my baby had her radiator etc replaced before I got her and that it is a common issue with these older bugs. If that gunk got in there and did some actual damage to the flow, may be that a new radiator is warranted. Especially if those hoses are cold when this problem is occurring. Unless your t-stat is a dud.

 

[red99]

Sounds like the radiator is plugged up as well. If the lower radiator hose is staying cold, the thermostat checks OK (heated in a pan of water on the stove) and the system properly filled then there must not be flow through the radiator. The heater hoses should begin to warm within a minute of startup and remain warm while the engine is on.

You say it ran OK but low heat after you flushed everything the first time. There was probably Bars-Leak in the block still which then circulated into the heater core and radiator and plugged them up again. If you replace the heater core and/or the radiator you run the risk of plugging them up as well until the Bars-Leak is out of the block and hoses. You may want to try a few more cycles of flushing and driving with the current parts to try and clean it up better. You may still be able to salvage the current heater core and radiator. Flush the heater core or radiator separately from the rest of the system (so the flushed water doesn't go back into the block again) and try to generate as high a flow rate as possible through them (without exceeding about 15 psi pressure).

 

[red99]

Oh, and be sure to flush in the reverse direction so you don't push the stuff deeper into the core or radiator. This means the water should flow into the lower radiator hose and into the heater hose that connects to the pipe going to the water pump. I successfully flushed a radiator once by putting a garden hose into the larger radiator hose and using vise grips to grab the extra radiator hose and make a seal around the garden hose. This forces the flow through the radiator to get a high flow rate.

 

[ERIKSEN K]

no over heat and not blend door the core is cold.

 

[jfoj]

Put a scan tool on the car and monitor the engine coolant temp.

It should hold around 205F/96C.

What does the lower radiator hose feel like when you have no heat?

If you had some sort of stop leak in the engine, I am guessing maybe someone overheated the car at some point and possibly the head gasket has been compromised?? I know you have tested for the issue, but you have also had an overheat.

So radiator, heater core, head gasket may be in question.

Have you connected a hose to the heater core to see how well if flows?

 

[ERIKSEN K]

When I flushed it I separated all the hoses and isolated the major parts I removed t-stat water outlet and pump flushed and back flushed all parts the rad is working I used my borescope on the openings and its clean no sign of stop leak anywhere. Using my inferred temp gun the rad is cooling as it should. I can pull the heater hoses off when the engine is hot and the hoses are cool there is coolant in it I t acts like there is an air pocket at the water pump but its flows coolant and is not over heating in the car I now have 2x water pumps and 2x t-stat.

 

[ERIKSEN K]

I own a solus pro from snap-on with euro/VAG hardware lower rad hose is warm and fans kick on at 210 car never gets over 220.

 

[jfoj]

Not sure what to tell you, it will not be the thermostat as the stat only should allow coolant to move between the radiator and the engine. Stat open or closed, you should have water flow though the heater core. Same holds true for the water pump.

I cannot find a decent diagram for the cooling/heater/water flow at the moment.

I do not see a water control valve??

My 2003 1.8t AVW engine will get warm air coming from the heater even before the blue coolant temp light goes out, less than 1 mile from when I start, maybe not hot, but it is warm.

There may be a restriction that is needed to force the water to flow via the heater core?? I need to find a diagram because I cannot see where the heater hoses connect behind the motor without getting under the car.

 

[jfoj]

The other thing is if you thing/know the heater core is not restricted and flows fine, you need to find what hose is the supply side.

If you disconnect both heater hoses with the engine running, one hose should have water flowing out of it at a reasonable rate.

If no flow, you have to back track to the engine block and look for a restriction.

A short cut, but maybe not easy with the heater core quick connects is to put loop of heater hose in place of the heater core, if the hose does not get warm, then you can easily rule out the heater core as an issue.

 

[red99]

When I flushed it I separated all the hoses and isolated the major parts I removed t-stat water outlet and pump flushed and back flushed all parts the rad is working I used my borescope on the openings and its clean no sign of stop leak anywhere. Using my inferred temp gun the rad is cooling as it should. I can pull the heater hoses off when the engine is hot and the hoses are cool there is coolant in it I t acts like there is an air pocket at the water pump but its flows coolant and is not over heating in the car I now have 2x water pumps and 2x t-stat.

OK. So maybe the only problem is the heater core. A plugged core could make an air pocket in the heater hoses that can't be cleared. Does water flow through easily when you flushed the heater core? If you disconnect both hoses at the pipes and pour water into one, will it come out the other?

 

[dnyed]

Maybe it's not the Turbo S that's a POS, but the PO......

 

[turboturbo]

Take the thermostat off, and jam your finger in and left to check the impeller on the water pump. If you can move it, it is not connected to the cog on the pump and your pump is bad. It could also be broken in pieces. I base this on your first post where you stated that the parts used were VW. VW uses a plastic impeller on the water pump, and it is a known failure point. Some aftermarket pumps are available with metal impellers.

 

[ERIKSEN K]

It is new style pump with metal impeller and the core flow’s coolant and water with no restriction. Tomorrow I am off work I am going to go get my c02 tester from my tool box and re test for co2 I think its air locking as of a head gasket being bad!I know I tested and it was good on the test but I am lost on this on?

 

[jfoj]

Unfortunately this is kind of what I was going to mention, however, I hate to tell someone the head this route if they cannot be 100% sure about a head gasket being bad. Obviously if you have a head gasket problem, it is a small leak.

Not sure if can perform a leakage test and check for bubbles in the coolant reservoir?? Sometimes these problems do not show when cold and with shop air pressure??

Good luck and let us know what you find.

Check the 2.0l section, there are a few head gasket issues lately that I recall also had heater problems, these may give you some ideas?

 

[ERIKSEN K]

re tested and it's a head gasket so yesterday I ordered a new cylinder head and I ordered an APR stage 3 turbo kit with Billy Bob exhaust system

 

[jfoj]

So an excuse to upgrade!

Smart move on a different head, saves time as you can get a reworked head ready to go.

Good luck, how did you finally confirm it was the head gasket?

 

[ERIKSEN K]

Yep I am using this as an excuse to upgrade so my head will be coming from VW yep I say it I got a dealer head!:biglaugh: