Funny coolant temps after rad change...

[Robbo149 0]

Fitted a new radiator on my VR a couple of weeks back, but not really driven it since due to hols. Got it out the garage today to take it for a blast & noticed the temp gauge didn't get much above 70. Checked the oil temp on the MFA & that seemed to be normal - rising steadily & topped out at mid 90s. Got back home & popped the bonnet to check everything out - all the hoses were nice & hot, heater working fine, oil temp settled at mid 90's. Left it running for a while to see what happened & the coolant temp quickly rose up to 110! - the fans kicked in ok, first at low speed, then second stage. No leaks, levels ok, but temp gauge didn't seem to want to drop below 110 when stood. When I was driving around, it didn't get much above 70!

 

Does this sound like an airlock somewhere? Or maybe a dodgy temp sensor?

 

Cheers,

Robbo

[VW_OwneR_85 2]

ive always thought mine had a problem, but i think its just normal, my temp gauge is like yours,just stays low on the guage although it can rise up to 85 90 on a hot day or left on idle, my fans also kick in when they should ,iv always thought it was lying to me!! engine bay just seems hotter then it is, iv replaced the 2 temp senders in the thermostat housing,think its just normal tbh..a way to tell if one senders lying is to hook it up to vag comm and get the temp reading on there and then see what the guage is saying..

[Robbo149 0]

I don't remember it getting that high before the new rad - it seemed to get up to 90ish fairly quickly & not fluctuate much before. If anything, I would expect it to run coooler with the new rad - oil temps are definitely lower now.

 

Cheers,

Robbo

[lewvw 10]

I just replaced my rad, and mine also now runs slightly hotter (up to 110 in traffic where it was previously around 100). I tried to get a genuine rad but vw dealer said it was obsolete. I then got one from euro car parts which was made in brazil and was thinner than the original rad which was quite chunky. Therefore I think it's running hot because it's cooling less coolant at any given time and also now obviously holds less coolant (which is pants). I'm gonna flush out my coolant system and replace the thermostat and housing and possibly waterpump as I dont think it was originally intended to run so hot.

[Critical_Mass 10]

Before flushing the system consider changing the blue temp sender on the front of the engine. Had this issue on my vr. the temp wouldnt go above 70 when driving but if the car was left to idle it would go up to 110 and fans kick in. Changed the blue temp sender and it sorted the prob

 

Obviously removing the temp sender will drain some of the coolant.

Edited September 4, 2011 by Critical_Mass

[tony_ack 0]

Before flushing the system consider changing the blue temp sender on the front of the engine. Had this issue on my vr. the temp wouldnt go above 70 when driving but if the car was left to idle it would go up to 110 and fans kick in. Changed the blue temp sender and it sorted the prob

 

Obviously removing the temp sender will drain some of the coolant.

 

Interesting - my VR has always done this - I had just assumed it was normal, but perhaps not! I wonder why the blue temp sender would do this though - isn't it just the ECU temp sender? It doesn't have anything to do with the temp gauge or fan controller AFAIK?

[Critical_Mass 10]

Sorry not the blue temp sender, that is indeed the ECU sender - my bad. The original is yellow, but i believe new ones are black, my new one was black.

[Supercharged 2]

What coolant mix? Genuine VW radiator?