That cooling issue again..

Used the van twice this year had a motorway run both ways to Edinburgh, not my favourite place to be in the van, I mean the motorway not Edinburgh... but the van went like a top sitting comfortably at 55 and returning around 30mpg .. ( 1641 with vacuum dizzy and twin solexes..... correction that should read webber ICTs which have been re jetted upwards ) .. Arriving at the destination everything was good no flickering oil lights or any other issues.. Weather wise that weekend it was definitely pretty cool . The return journey was the same.. great run in heavy rain and cool temps and not a hiccup.

Last week I decided to use the van for a 20 mile journey, bright sunny day and plenty fuel in the tank. outward run was good sitting around 50 most of the way on single carriageway B roads .. Van sat all day until the return journey. set off as the teps cooled, drove the van pretty much as I always do I pulls clean in top but usually drop to 3rd if it drops below 35 even though it pulls cleanly from 30 in top..

Anyway, I get home the last leg of the journey being a haul up a steep hill which it does easy in 3rd..

I got to the house and noticed the oil light flickering .

I got the van parked up and checked the oil.. The dipstick was hot, but could be held comfortably .. the oil on the stick was still cool and vicious . Left it for a bit before checking the level and the level was spot on .

Checked the thermostat at the time and it was fully extended .. all tins are in place all seals intact, no oil leaks ,

Im stumped... maybe just a bit paranoid but it is annoying me .. thoughts are toward larger main jets to overcome the crap ethanol rich fuel we use these days , maybee smaller air correction jets to keep the mix richer??

Oil is old school 20/50 Castrol GTX ..

Im beginning to think it would be easier to reliably cool a subaru motor .. which I have in the wings

Any ideas ?

Am I driving the van wrong, should I be revving it harder .. especially in warmer weather??

 

Just wondering if you have a VDO oil pressure guage fitted ??

Reason i ask is because the VDO switch will flash the oil light at 8-10 psi whereas standard is 3-4 psi ...

Just a thought

 

Just have the stock bog standard run of the mill switch and warning light ..

should add that the underside of the engine was pretty hot .. I could touch it but it was hotter than the dip stick.. I understand the sump / casing is a huge heat sink and will be pretty hot so the touch test might not be a great indication of the motor running hot ..

This was also new crate motor not a reconditioned engine .. done around 12000 miles in the last 3 years, regular oil changes , most of the time the oil is barely discolored, always topped up, had stock black valve covers. silver powder coated tins, natural alloy block .. Heater works great .. via NOS VW heat exchangers and I run with it on/ open all the time ..

 

Rules that out then ...

 

Oil light flickering after a long hot run indicates low oil pressure...worn internals methinks. Is the cooling system working properly. Maybe don't labour it in low gears.

 

For the sake of a tenner, i would try a new oil pressure switch first.

 

Im pretty confident its not wear, its only happens when the air temp is higher on warm sunny days... which is why its so annoying sonce its nice to use it on warm sunny days .. Drove it all over the highlands and not a single issue, drove it down the motorway at a steady speed 70 miles non stop, no issues , as soon as the weather gets decent and its driven "normally" the oil light flickers should have said at idle ..

Give it 20 mins fire it up its fine .. sometimes after a bit of a run in hotter weather I would reach the destination and sit with it running at a higher idle for a few mins then back off the throttle and it would be fine . I dont cherish the van, but I don't want to grenade it and incur a £3k expense for a new motor.. If its just a matter of revving it harder in a lower gear or richening the mixture .. cant be the only van on here where the oil light flickers at idle after a decent run on a hot day ... but is there a fix ?

Its got a stock pulley on both the crank and the alternator ..

might try the switch ...

 

As above, most likely tired bearings. How old is the engine? A Bay should easily behave itself in UK temperatures, at higher speeds than you’ve been doing.

 

3 years old and 12000 miles, Tired bearings ? with oil changes every 800 miles and never hammered ...? seriously .. its not a recon, it was a new crate engine carefully run in and it only does this on warm days ... If it were *****ed bearings it would surely do it all the time.. ?

Yep sure the flickering oil light denotes low oil pressure but its oil thinning due to heat in this case, not wear.. otherwise it would be flickering all the time ..

Its not an uncommon issue but no one seems to have a solution.. mixture and timing seem to feature in stateside and aussie web pages as a cause , but there are never any results of changes discussed, was wondering if anyone has had similar issues and remedied it with mixture / timing tweeks. Looks like I will just have to experiment .. Im ruling out wear since it only happens when the outside air temp is higher..

Probably thinking about selling the bus next year but would like to solve the issue before I do.. I love the bus but im just not that interested in using it unfortunately ........ Having built it myself I know every inch of it and the only part to give me any cause for concern is the engine which is disappointing as its the single most expensive part I bought , and went for new over recon .. Saying that and meaning no disrespect to other suggestions but I dont think its a physical engine problem..

 

what speed would a 1641 bay window sit at for a prolonged period ? most of the ones ive driven belonging to other folk are lucky to reach 50 if your brave enough to take them there .. fastest ive seen on the digital speedo inmine is 68 downhill .. it will do a steady 55 all day with an occasional run at a steady 60 but I tend to keep it between 55 and 58 on the dual carriageway and really never hammer it ..

 

Just a thought
Oil circulation problem or blockage somewhere
You do change the strainer and not just undo the big nut to drain?
You can’t have a worn out engine
One day and not the next
After a run it should all be reasonably hot including oil
Try 30 grade oil in it see if that helps

 

We have a 1641 with a similar setup, slightly older but similar mileage. Last year in France during the heat wave we had a bit of a dash to the tunnel. Did 3-4 hours at 60-65 on gps and it was spot on, no oil light flickering and it pulled well all the way.

We were fairly well loaded as well with holiday gear

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Is your engine full flowed, with an external oil filter? If so, you could stick a small external oil cooler underneath, via a thermostatic sandwich plate for minimal cash. Could give you some peace of mind if nothing else. I think @mikedjames did this on his 1641?

 

The engine oil needs to be above 80c to reduce contamination from combustion. IMO holding the dipstick simply demonstrates how an individual can tolerate heat, but 80c is too hot to touch and so is 100c or 120c, you have no idea what the temperature is.

The oil system attempts to control oil viscosity and temperature with a pressure relief valve. When the pressure is high the cooler is bypassed to heat the oil, conversely if the pressure is low oil is passed through the cooler to thicken it, but the temperature change is far from instantaneous. After a long run the oil has reached normal temperature, if you slow or stop the oil temperature remains the same. The pressure reduces because the oil pump slows but there hasn’t been sufficient time for the oil cooler to reduce the oil temperature. That’s probably what you are seeing – if you allow the engine to idle for a few minutes the oil temperature should reduce, the pressure will increase and the oil light will stop flickering.

If you’re worried about the flickering oil light increase the idle speed.

 

I would try a different oil. I’d go for a multiflavour but mineral based oil such as the Halfords one for Classico veehicckles. I’m not sure if the synthetics are robust enough in heating and cooling properties, as in great first off they’re great but easily knacked by an Aircooled’s demands of heating and cooling, whereas a mineral based oil will cope for longer. I’m guessing you’ll want to try an oil change , so try this. I also have the same motor and I’m not filled with confidence I’m afraid, but mineral will help.

Ozziedog,,,,,,,,,,,, go on then you lot, argue about that then

 

I've driven from Italy to UK a few times....long periods of sitting at 55mph...no problems...
The bus would go faster

But what's the point anyway...

 

Good spot on the oil Ozzie, mineral is the way to go. I was told a 10/40 on a non tired engine and it's worked well for me. Halfords have stopped selling it now though

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Castrol GTX 20/50 is mineral oil always used that or other quality brand 20/50. but comma mineral 20/50 is probably just as good considering the frequency of oil changes @800 miles ..

motor is not full flowed, standard dog house cooler.

 

what timing settings are you using and what carb jetting.. ? I swapped out the crap jets in the new solexes for larger mains and corrections, van runs great, starts on the button and would easily sit at 60 but I choose to keep that little bit in reserve for cornering when there are audis on my tail..

 

I always had it in my head it was a semi synthetic, something learned!

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