oil cooler

hello eveyone ive notice that after a half hour drive in the mk1 that my oil cooler does not get that hot i no that it come on at a sorton
temp . but even so it does not fill like it doing it job right . does eneyone no eneything about them .or may be there just not that good  :dontknow:

It is thermostatically controlled and doesn't pass oil until about 100 degrees c. if I remember correctly.
You need to be giving it a dam good thrash down the motorway for it to open! :wink:

My oil is running at 130deg C constantly on motorways / dual carriage ways….do I need a bigger oil cooler??? It never gets hotter, but won't get back down once up there, if i keep driving!!! Is it a big problem? Engine temp stays pretty much normal!

I have 172 Kent cam kit in my '83 1800cc GTi - which obviously increases revs.

Really struggling for ideas…only started happening after the last oil change. I suspect my mechanic has switched from Miller Mineral Oil (that I was using to good effect) to a synthetic / semi-synthetic - would this even cause the problem????

Help greatly appreciated!!!

Old-GTi

Can't believe a few extra revs would cause it. You would seriously need to be pounding it to get it any where near those temps and even then it would come back down when you eased up.

Does the oil filter housing feel that hot? You would instantly boil water on it if you dripped a drop on it at those temps

I would either try another sender or mount a thermometer to the top of the oil filter housing. It sounds like its getting a defunct reading or the mfa is giving out duff info. I assume thats what your reading and not a separate oil temp guage?

It only happens if driving at 65+mph for 15mins or more on dual carriageway / motorway. Engine temp regulates ok, but it does get warm inside the car! So it may be getting that hot. Can't say that I thrash it, if I ever give it a boot its only for a short while and then back to a steady cruise -certainly never persistently have it cooking at high revs.

mfa reads random temps. like 152deg C or 2 mins later 60degC….

I have a set of VDO gauges in the center console….its the VDO gauge that reads 130degC. It always used to read 90degC steady as a rock until last service / oil change. As I've just got it out of the garage for 'summer' again it will be serviced / fresh oil next wkend! To be honest haven't tried the water test…but have been reluctant to get it up to that temp regularly - I've been keeping it to short little spins for 20 mins max 60mph ave. 40mph!

Mystery???

Posted more detailed account on this thread!!

The Mk1 Golf Owners Club

The original oil temp guage in the MFA is just a gimmick any way and if you didn't have the VDO guage you wouldn't be worried about it…..what the eyes don't see etc etc!

Have you checked the wire to the sender? Your mechanic hasn't knocked it off, has he, and its going to earth when bouncing along the road?

Type of engine oil shouldn't make much difference as the oil acts as the medium to transport the heat away.

For piece of mind i would try another guage and sensor or get a suitable thermometer and strap it to your sump pan.

I had checked the wiring - looks ok, will check with multimeter today. Then i'll give the thermometer trick a go and check back with the result!
If the themometer reading closely match the VDO gauge then I guess I will just need to look at improved oil cooling?

Thank you very much for the advice…hope it's just a duff gauge or dodgy earth!!! Fingers crossed

old-gti said

I had checked the wiring - looks ok, will check with multimeter today. Then i'll give the thermometer trick a go and check back with the result!
If the themometer reading closely match the VDO gauge then I guess I will just need to look at improved oil cooling?

Thank you very much for the advice…hope it's just a duff gauge or dodgy earth!!! Fingers crossed

If it is getting hot (which I doubt), fitting a larger oil cooler isn't going to solve it. You will just be fixing the symptom not getting to the cause.

Let me know what another thermometer says.

Very True about the symptomatic solution! I hope I can get to the route cause. That said if the oil is cooled then the associated risks and damage to engine are reduced. 7

I'm torn over the correct oil to use. Millers Mineral worked at keeping temp stable before - but from what I read this is tosh - it must be something else. Fully synthetic oils like Mobile 1 (although pricey) do not have additives that can sheer and cause sludging - on the flip-side reduced Zinc / Phosphorous levels in modern oils can lead to increased friction/temp/damage on flat profile tappits / valves on older engines…..all the reading hasn't helped me come to a clear consensus!!!!  

I am toying with getting the car out in the rain today to get a temp reading - but it is still persisting it down here in Staffs. If / when I get it out; I'll post the temps back on here!

I can't help but think that it has to be something that changed at last years annual service. However again, I may be being short sighted; many things change as we all get years old - our cars must be the same. At University I could easily hammer 10pints + a night out and skip to lectures the next day and now…..5 pints and the wife is scrapping me up off the floor!!!!

Many thanks for your help!

You can have oil too cold you know. I wouldn't worry about the oil used too much neither. Remember these engines were put in Audi's nearly 40 years ago. Back then it was just standard 10/40 multigrade. I just use a semi synthetic which I guess is a compromise between old and new.

Its modern engines which you have to get the correct oil like the modern PD VW engines. These have high sheer streeses on the cam gear and injectors and you will knacker them by using the wrong oil.

I've just had my engine apart for it to be balanced. When I put it back together the oil pressure switch didn't work. No reason - just disturbing it made it fault. But now its OK again :dontknow: Strange things do happen at coincidental times sometimes.

Okay…the results:

I got the car out today. I drove on country lanes max 60mph ish ave. 40mph for 20mins. The VDO gauge read 90deg C after this gentle run in. I stopped the car, felt the oil cooler - it was warm but I could happy leave my hand on it - without it getting anywhere close to uncomfortable. I took a digi-thermometer reading off the oil cooler = 38degC - (about right - like the hot water tap in the house). I tried to get a reading off the base of the oil temp sensor = 40degC - tried sump-pan = 38.5degC, then I pulled out the dipstick and dripped a spot of oil onto the prob = 42degC!!!!! I noticed that the wire to the oil temp sender was wobbly - so i pushed it on securely (connection looked ok either way).

Then I decided to go for a buzz up the dual carriageway - I ran it at 70mph for 15mins there and 15 mins back. The VDO gauge never left '90degC'. Repeated digi-reads = the same as before across the board. Then I decided to give it some welly - accelerated harder on the 'on ramp' and did 'approximately the national speed limit' for 10miles - to better replicate modern motorway driving speeds. Finally the temp on VDO gauge left the 90degC mark and rocketed to 100degC…..where it stayed!!!!!!! NO WHERE NEAR PREVIOUS EFFORTS!!! So I dropped back down to 65mph ish and the VDO gauge responded within 2 mins and the oil temp reading came back to 90degC. I then drove another 16 miles on country lanes and the oil temp behaved itself properly!!!!

Only differences between last weekend and today - ambient temp last weekend ~27degC, today = 11degC. Last weekend I drove persistently at 70mph for 1hour dropping to 50mph to try and get temp down - AND oil temp hit 130degC after 15mins. This weekend had to 'try' to get it hotter.

Last summer I drove back to Yorkshire in the evening - ambient temp started at 25degC probably dropped to 15degC during journey - if I remember correctly the VDO gauge stayed at 120-130degC regardless.

So:
1.Can 16degC of ambient temp really = a difference of 20-30degC in oil temp?
2.Was the slightly wobbly temp sender connection to blame?
3.Will be planned trip to the Nurburgring in September lead to a cooked engine or will it be ok?! - Who knows!

I will of course repeat tests if we get a warmer day and report back. Still a bit of a mystery to me!!!

regards

Old-GTI

I have another idea you can try to prove / disprove its your temp sender or guage.

You can either take the sender and guage out the car and bench test it with boiling water or if its too much hassle take the kettle outside to the car.

Take the temp sender out the engine,  while the mrs isn't looking nick the kettle and as your leaving the house drag an extension lead out with you. Extend the temp sender cable enough so you can dangle the unbolted sender, using the cable into the kettle, so it just touches the water. You also need to earth the body of the sender to your car with another wire somehow - Try holding the earth wire to the sender with a clothes peg or something. The other end of this earth cable I would attach near to the location of the sender at this stage but leave it long enough to reach into the car as this will serve a purpose for the next step of the experiment

 Switch on the ignition (but don't start it as you will empty all your new oil underneath the car!) and boil the kettle.
Once the kettle reaches boiling your guage should be reading 100degsC.

If it isn't then you have either a dodgy guage/sender or earthing.
Now unbolt the made up earth cable from the engine block and take it inside the car and attach it to the earth wire of the guage. This will eliminate any ground offsets which maybe present and repeat the 1st part of the experiment. If the temp reads the same its not the earthing.

Well…
Many things have happened since the last post.

Oil change and oil filter change (as well as securing the contact for the oil temp sender), this lead to a month of no problems. That said, I never met a traffic jam during this time. Oil temp remained at 90degC throughout normal running. After getting the car serviced, I set off with my brothers for a visit to the Nurburgring. I had been given an Aston Martin experience for my last milestone birthday, thought that taking the GTi back home would be fitting.

So, she behaved impeccably all the way from Staffordshire through England, France and most of Belgium. Then the first traffic Jam. Very quickly oil and water temps rocket. After 20mins, (15 with heater at full blast in 25degC outside temps) I was desperate for a place to ditch and wait for it to cool. Then everything cleared and we're off. Drove slowly (60mph on motorway) for 10mins, the car cooled a bit, then stopped for a break. Everything settled.

All fine with short journeys in Germany. When it came to fill up near 'The Ring', only available local garage had very strange fuel options. Ended up talking to a german petrolhead, who convinced me the 'super 95 with 5%bio ethanol' was the closest to  euro 95% octane. I filled up. Then came the return journey. 30 mins in, first autobahn….going approximately quick for max 1min, pooring rain, car running great. Back off the throttle cruised back down to 70mph still off the throttle and THEN POP!!!!! White smoke, fills the 3 carriageways. Pull over, car temp ok, oil pressure never faltered, suspect blown head gasket. Little option (due to ferry crossing), have to carry on tentatively, then gain confidence normal 70-80mph motorway speeds. Sop start a number of times. Car starts fine after 2hr ferry crossing. Longer story short, car runs spotlessly all way home even at 70-80mph. No oil in water, water in oil, no sweet smell from exhaust. No major signs. TBC……

Now, car runs well, (as before, fine if moving) but rad fan has stopped working and overheats If left at idle. I suspect that this may be pre-existing. Getting head gasket checked out, but no hydrocarbons reaching rad. Cylinder Pressures to be checked.

It's been suggested that 'POP' & white smoke could be bio ethanol exploding off hot exhaust. My university chemistry tells me that with such a large ammount of smoke, this is unlikely… Must be said, I didn't 'feel' the pop and other older cars were on the road…but I'm pretty sure it was from mine.
Another Mk1 addict suggests bust thermostat, getting very hot and then opening and blitzing through coolant!?! Sounds far fetched…..

Ongoing………..

Big thank you to Bert for having a look at the head gasket yesterday.  8)

Head gasket is fine, as suspected!!!    One off white smoke may indeed be exploding bio ethanol Atfter all!   :dontknow:

Thermostat is working, fan is working, but the coolant is cack. Despite asking my local garage to bleed the rad/coolant and replace before my Germany trip - they seem to have done nothing of the sort. I was in such a rush the day I left, that I never even checked! There is only old crappy water in there and there is loads of crud. Bert suggests that draining it all, washing the cack through and replacing with a 60:40 mix of antifreeze coolant:water cold to solve all my worries. Otherwise car is running mint!!

I will be getting onto this probably next weekend!!! I'll update with the results!!!  

Old-gti