Last message before I remove the water pump from my VR6...

[Funkster 0]

'lo all,

 

When driving normally in clean cool air my VR creeps up over the 'stat temp, usually settling at about 90. This clearly isn't right and it didn't do this a while ago. Putting the heater on full helps to cool it.

 

I have:

- checked the top and bottom hoses (by poking around in wire and by squeezing to feel for any loose or broken bits)

- removed the (broken) restrictor in the top hose in case it wasn't letting the levels equalise

- poured water through the (nearly new) radiator to check it flowed freely

- checked that the 'stat is opening in a pan of water

- replaced the header tank cap

- flushed the system with wynn's cooling system flush

 

... and probably some other stuff I've forgotten about. The 'stat housing bits and the crack pipe were replaced a few months ago due to them all being cracked.

 

The heater is very efficient, and having removed the restriction from the header tank bleed pipe there is a steady flow of water from the top hose into the header tank, which to me would suggest that the pump is working, but is it working well enough? Not sure how to tell really.

 

Any clues or other suggestions before I start taking all the necessary bits off to get to the water pump?

 

Many thanks,

--

A frustrated Olly who's missing his Corrado (been off the road for 5 weeks now...)

[andy 0]

Unless I've missed something...... I can't see whats wrong here. Whats wrong with 90? Both the VR6s I've owned have run around that temperature with no problems.

[Funkster 0]

Well, the 'stat temp is 80 and the car ran well for a while bang on 80 on the gauge. Then all of a sudden it started creeping up. The bleed hose restrictor blocked itself and caused it to get really bad, so I cleared that and flushed/changed the coolant. It's been running constantly over 80 ever since.

 

If I hoof it on the motorway, it goes over 90 which certainly isn't right. Also the fans don't come on until way too late due to low temperature in the bottom rad tank.

 

I know they tend to get hot, but when driving at a reasonable speed any engine should hold solid at the 'stat temp and I don't want to warp anything. I'd also like to be able to hoon it round a track without it melting!

 

Ta,

--

Olly

[andy 0]

I understand your concern....but as you say...they do run hot. I can see that an engine will try to hold stat temp, not sure that it will though. It depends on the efficiency of the cooling system in general. What temp are the fans specced to come on at? I'd check the sensor controlling the fan if your in doubt. I'm not saying I'm right by the way, I don't drive mine "normally" that much and it regularly sits at 90 and above....well above!

[Funkster 0]

Stage 1 fan says ~92, but with the engine idling on the drive the other day it went to about 105 and the fans still hadn't come on. I fitted a new thermoswitch a couple of months ago.

 

If it had always been like this then I would be a bit less concerned, but it's the fact that it's changed that makes me worry.

 

Oh, it's done 154000 miles by the way...

 

Muchos gracias,

--

Olly

[Storm 0]

Sounds like it could be an air lock when you replaced the coolant. Its supposedly a knack to get it right.

[Funkster 0]

I did wonder about that, but the level seems consistant. I filled the system via the top hose, I think I read somewhere on here that that helped prevent airlocks. I'd be thrilled if that was what it was though... any hints for a better way to fill it?

 

Thanks,

--

Olly

[andy 0]

I wonder if your stage 1 is working, are you sure that the fan is working at both speeds? It almost sounds like stage 1 is being ignored then only coming on at stage 2 temp?

[Funkster 0]

Last time I checked stage 1 worked just fine, and stage 2 didn't work (though it has done previously - not sure what's gone wrong there).

 

When I've had the fans come on previously, it's been stage 1. Curiously when I shut it down just the other day (with the gauge reading over 100) the after-run fan didn't come on. Not sure if this is significant.

 

Thanks,

--

Olly

[Roger Blassberg 0]

This sounds as though your yellow sensor is starting to play up. It controls the fan/pump run-on and, I am told, the temperature gauge input. I suggest you change it and see what happens. It's relatively easy and cheap, certainly more so than the water pump. Your temperatures may be normal but are being signalled as too high by the faulty sensor.

 

Best wishes

 

RB

[theRuler 0]

when you are putting the water in, run the engine.

get it hot (so the fans kick on, stat opens) and top it up some more.

 

if you suspect your fans aint kicking in early enough, rig a switch to them so you can control them until you sort it properly.

 

hey funkster my vr6 has done similar miles (150k). i had a bunch of cooling problems that eventually turned out to be a leaky head gasket :(

[Funkster 0]

I do wonder about the yellow sensor, but the oil temp creeps up as well so it does seem that the engine really is getting hotter. I shall order a new yellow sensor anyway just for peace of mind as it is as you say a damn sight easier than removing the pump.

 

I'm hoping it's not the head gasket - compression sounds good across all pots when cranking and it doesn't seem to blow the coolant out, but then again these aren't perfect indicators.

 

If anyone can tell me the right part number for the yellow sensor it'd be greatly appreciated - I've got ETKA on the way but it's not here yet, and I don't trust the dealer to get the right bit over the phone.

 

Many thanks for your assistance,

--

Olly

[Roger Blassberg 0]

Looks as though this has been discussed on another very recent thread, under "Yellow sensor...."

 

Best wishes

 

RB

[Funkster 0]

Indeed, although there is some confusion about whether the VW black/blue replacement is the right part. I have ordered what they told me was for the gauge, so we shall see!

 

Cheers,

--

Olly

[Funkster 0]

Hokay. I got the new black/blue temperature sender and it works just fine. It also seems to have sorted out the run-on fans, which came on when I shut it down at 100 and seemed to trip out at about 93ish. When sitting stationary the stage 1 fans trip in and out and hold at a steady 100 which I gather is normal.

 

Aside from that, it's still hotter than I would like despite changing the thermostat again just in case. It doesn't seem to matter what load I put on the engine or how fast I go, it fluctuates a bit but generally hangs around 90. Very strange.

 

I'm going to monitor it over the next few days and see if a rise in ambient temperature causes a rise in gauge temperature (and thus deduce if the pump has run out of flow). I've also got an OBD lead on the way so I can see what temp the ECU thinks it's at and if there's any other faults on the engine that I should know about.

 

Cheers for now,

--

Olly

[Henny 0]

90 is pretty much spot on for the water temp in any corrado... If anything that's a little lower than average for a VR! 8)

[saysomestuff 0]

10 degrees isn't much in terms of fluctuation is it? Mine runs at 90 dead all the time. Except when the termostat sticks closed and explodes my heater matrix in my face lol

[Funkster 0]

Indeed, and it's not extremely over-hot as engines go so I'm not *too* worried about it. However, it did at one point cool perfectly and stick right on 80 even when thraping down the motorway. It's the change that concerns me - seems like something is on its way out.

 

My OBD lead has just landed on my desk so I shall have a play with that later on.

 

Thanks for the support,

--

Olly

[Funkster 0]

No engine faults showing in VAG-COM, although it seems my front right ABS sensor has gone for a burton:

 

Address 03 -------------------------------------------------------

Controller: 1H0 907 379 E

Component: ABS/EDS TEVES 04

2 Faults Found:

00285 - ABS Wheel Speed Sensor: Front Right (G45)

35-00 - -

00285 - ABS Wheel Speed Sensor: Front Right (G45)

04-00 - Mechanical Malfunction

 

 

Coolant temp reported by the ECU was if anything slightly higher than what the gauge was showing. I'll have to sort out batteries for my laptop 'cos it only works off the mains at the moment and I'd like to see what the ECU thinks the temp is while driving.

 

Cheers,

--

Olly