Former VWDieselParts.com Forum

I've never changed the coolant myself.

Bentley's says that these hoses(labelled "1" in the pic) have to be loosened/removed/slid back. Maybe take the cap off of the fill bottle.

What about the heater core???

Bentley's says to reattach the hoses and fill through the overflow bottle, run the engine and refill if needed. Will this method get all of the passages full??? Are there any tricks to doing this???

How is the engine cooling system flushed...I mean really cleaned out???

The lower hose identified as #1 is the lower radiator hose. You have to remove that hose, and then the thermostat is in the flange between the hose and water pump. If the coolant is closed, the tstat will be closed, and that's why they say to remove the other hose identified as #1. If you do it when your coolant is hot, the tstat should be open and it will all drain.

I've always used something like Prestone cooling system flush to flush mine. However, if your case, I think you need to remove and inspect your radiator before you go too far. Verify how plugged up the inlet side of the radiator is, as best you can and manually clean that out of the car. You've probably got lots of that gook in the incoming radiator side tank that needs to come out.

For filing the system, I've always filled the overflow jug up, started the car, and then kept adding more until it quits sucking it down into the engine. You've got to have the small line going to the jug moving coolant/air though to do this. These VW systems pretty much self rid themselves of air due to the flow through overflow jug design, that's the high point in the cooling system where the air collects.

This "gunk" is a real unknown and not worth dealing with at this age of my vehicle. I am going to bite the bullet and purchase all new components and be done with it. After all, I have spent very little money on this car in 23 years !!! She deserves the treat !

When you do the flush, what keeps any crud from clogging the radiator and heater core again?
Do you have to back flush the radiator and heater after the flush procedure??
I guess the heater core can be flushed with it in place. Can the radiator be flushed in place???

What is the flush procedure??

Thomas M wrote:When you do the flush, what keeps any crud from clogging the radiator and heater core again?

When you do a typical cooling system flush, solids aren't present. Your situation is unique.

Thomas M wrote:Do you have to back flush the radiator and heater after the flush procedure??

If you remove all the solids from the system before flushing the system, these can be included in the overall system flush. You will probably need to remove hoses, tstat, etc and use a hose and flush through the block to try to remove all bits that you can. As mentioned above, you situation is unique because there are solids in the system. You need to remove those solids before installing new components and potentially plugging them up.

Thomas M wrote:I guess the heater core can be flushed with it in place. Can the radiator be flushed in place???

I wouldn't. I'd take the radiator out so you can look into it, rotate it, shake it so that you can make sure you get 100% of any solids out of it. If you are buying a new radiator as your buying new everything comment suggests, then the only item you would need to fully flush would be the block. Once that's properly flushed, then installing new hoses, water pump and heater core and radiator should have them in a clean system.

I'm going with all new parts and antifreeze.

I will drain the system every couple of years.

Thanks for all of the tips.

I have a post on here somewhere that shows how to drain the engine and radiator.
Maybe search with the term "easy drain" and my username.
Bump it when you find it because it hasn't been seen in awhile.
Otherwise, just pulling the hose and thermostat make coolant go everywhere.