Mk2 overheating

[physicsfool]

Evening all,

Rebuilt 1341, full blend, lairy cam. The lot.

Currently running it in, but having problems with overheating.

Checked so far:
Air in cooling system
Timing
Fuel seems to be getting to the rail fine.

But I am seeing temps of 110/100. I hit an a road and the lot cooled down to about 90/100 but as soon as I hit town/hills again it all got too hot (110)

Any suggestions on what I could try. Will be popping different sensors in tomorrow but beyond that I am kinda stumped. Is the set up always going to run this hot in such close proximity?


The engine starts pissing out water from expansion tank so the coolant light comes on. So it's defo getting too hot


Cheers

[DaBigGinger]

Is your radiator fan coming on? Assuming its not, sounds like a bad fuse, fan, wiring (earth?) or fan switch.

[runforrestrun]

Yep good point. Does the fan turn on?

[GR40]

Did you change anything up front!? Like a front mount along with your 1341 rebuilt! I had a similar problem when I added my front mount intercooler! When rolling the temperatures where fine but as soon as I hit an uphill or heavy traffic the radiator didn't get enough flow. My solution was a better placement to allow more flow to the radiator!

[physicsfool]

I will check on the fan, I can't remember it coming on, also yes my fmic sits right in front of my radiator and I had to downsize to fit the gap. Which is why I fitted an oil cooler.

May have to look into mounting the fmic elsewhere, or get myself a mk2f shell again

[Etches]

Don't be silly! Just put the fan on a manual switch if the worst comes to the worst dude.

Pull off the thermistor plug off the rad bridge it with a paperclip or summit and the fan should come on. If the engines that hot and the fans not then replace the thermistor in the rad. If you can't be bothered with that then wire a switch into the car for the fan, just a little annoying having to remember to switch it on and off!

My intercooler fully blocked my old radiator but it never ran hot even with a shitty slimline single speed fan.

Is the water actually getting to radiator to start with ( Delta t over the rad??)

[physicsfool]

Thanks for that Tom, so fan runs with paper clip but not on the thermistor. So looks like the sensor is buggered.

Hopefully once I have replaced that my temperature won't exceed 90. Feel a tad silly for not checking the basics first.

Will report back on how it goes.

Drives nicely though.

[Jacque]

My G is down with a waterleak from under exhaustmanifold
(probably because of running hot like you, my fan sensor is also hammered & long time in the shed...)

So best not to let it get to that point (like i did lol) i did nt drive near towns much so there was no rush...)

[physicsfool]

Yes I have gone ahead and bought a VW fan sensor, cost me £30. Hopefully that will sort it. But it was initially leaking from the back of the block where the water pipe attaches to the water pump housing but sorted that with some sealant.

Will know if the sensor makes a difference this weekend, will also double check to make sure any air bubbles are out of the system

[SuperMario]

Any joy with this.?

[physicsfool]

So fan still isn't kicking in, was told there is a relay for it. So looking into that. I have invested in another thermostat as this doesn't appear to be opening at 80 as it should.

Also bought a new febi coil pack from a local motor factor and it's packed up after 30 miles. Not impressed so put the original one I found in my box of spares back on. Don't make them like they used to.

Car sounds and drives really nicely, idles at 900 and with the lightened flywheel it picks up quickly.

[physicsfool]

So after all my poking/prodding, changing of thermostats and sensors it will the location of the top rad hose and the U from the metal coolant pipe.

Always turns out to be something simple. But at least it's stopped over heating and I can get on with running it in

[Jacque]

can u repeat that? 

[physicsfool]

Spot the error