new member!! hi guys.
I have a 1998 audi a4 2.6 5v with about 175xxx. bought it a couple weeks ago and it runs hot!. about two bars past half way, between the C and H. the oil cooler isn't hooked up, i have really good heat, the inlet tube to radiator builds up pressure and is warm, but outlet is cold and has little pressure. I'm thinking maybe a water pump because i know the plastic fins get old and worn but i'm not really sure..please let me know what you think!

 

I suppose first thing is does your gauge return to zero when you turn the ignition off? Have you replaced the temp sensor? - the temp sensors and gauges are both fairly common failures

Your probably due (or way past due) for a timing belt too.. The water pump is typically changed in conjunction with the timing belt anyway..

 

Start with temp sensors, cheap and easy. Next stop would be thermostat and waterpump. Guessing you got the vehicle for a nice deal, I would spend the $$ to get the timing belt service done and know at least the most volatile of the maintenance items is complete and functional. Knowing you have a fresh/strong waterpump will help in diagnosis of temp and flow problems. if you can wrench yourself I would suggest looking at blauparts.com for a timing belt kit.

 

With the car at temperature, see if the radiator is warm uniformly across its surface. The fact that the upper hose is cold means coolant isn't circulating. Either the remediation is blocked or the thermostat is stuck closed.

 

Like he said, if the upper hose is cold, it could also mean that there is no flow of coolant due to the water pump free wheeling on the shaft.

There's a lot of stuff that it could be. If you're in the US, most of the country will be hot this upcoming weekend, so any cooling issues will become urgent problems if you plan on driving.

 

sounds like a thermostat to me

 

the upper hose is hot as i stated in my original statement not the lower one.. brought it in cz there was a leak on my oil cooler and they totally rerouted it and there are no coolant hoses to the oil cooler now..... not sure why they did this... should i have it put back to the original way? doesnt ever **** coolant though, just runs about two clicks over normal halfway temp, from my own process of eliminations i think it is either a faulty temp sensor or water pump. leaning more towards a water pump. thermostat is fine cz i have great heat!.

 

i'm guessing a water pump. so i'll probably go and pick one up today and put it in. see what happens!