1.5NA cooling troubles

[mnoll406]

Hey Guys,
I have a 80 rabbit diesel with the 4 spd. I have replaced a thermostat, and radiator, and the car has never been overheated. I replaced the radiator because the other had a slow leak and it was original. It was the large brass type. The new one is aluminum/plastic. I live close to Palm Springs, Ca. In other words the desert. In town, at idle, and when it is below 100F. All is good. But on the highway, 70+ mph, and over 100F the temp gauge gets into the orange zone. I pulled over and let it idle, and the temp came down. I will be purchasing a VDO temp gauge to see "real" temps. Any idea's what the problem could be? I have not replaced the water pump yet. Also I have a 1.6 I will be turboing so is there a waterpump upgrade that will also fit the 1.6? Would a 1.9 waterpump work? Would it be an upgrade? I have A/C but am in the process of repairing it so I am not running it yet. I also bought some redline waterwetter and will be putting it in when it cools down. The coolant was just recently flushed, and before replacing the rad. I did a coolant flush. What about adding a aftermarket rad fan, or 2? Thanks,

                                                Mike

[tylernt]

A rad fan won't move any more air than going 70mph will. How's your lower radiator hose? It tends to collapse at high rpm which restricts water flow. Also, I have had V-belts slip without squealing -- how old is the belt and how tight do you run it?

How's the injection timing? Significantly advanced will increase power but also heat.

Have you tried the jam-a-screwdriver in the waterpump impeller test?

[mnoll406]

Hey Tylernt,
All belts brand new, all rad hoses brand new. Belt and injection pump set to factory specs. What is the jam a scewdriver in the impeller test? Won't this fry out waterpump or make the belt slip? I have looked in that hole and have no coolant leaking. It could also be the factory gauge is off, have not ruled this out yet.


                                       Mike

[tylernt]

The screwdriver test is this:

Remove the belt. Remove thermostat and look in the resulting hole towards the passenger side. You should be able to see the impeller fins. Gently place a screwdriver tip in there in a manner that prevents them from turning. Now turn the waterpump pulley with your hand. You should be unable to turn it with the screwdriver in there. If you can, the waterpump is bad.

[vanagonturbo]

try this. I could be wrong, but it sounds lik eyou have addressed everything except a headgasket.

Have the cooling system pressure tested. There is a tool that connects to the expansion tank and is used to pressurize the cooling system to check for leaks. This same tool can be used to check for a leaky headgasket.

Put the tool on the bottle, hold the rpms around 2500, make sure the fan cycles. If you are getting readings higher than 10 psi, you most likely have a blown headgasket.

You did use German replacement parts right? Non German units are not as good of quality.

[fspGTD]

Moved to troubleshooting.  IDI engine is for power enhancement related discussion only.