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Discussion Starter #1
Greetings once again,
This time I'm very confused. I have the GTV 2.0L '85 model and my oil pressure is not acting right. When cold (below 80) she is a beast, flying everywhere. Once she gets to operating temp, the pressure wont go over 4 bars and she is, well feels like a VW...
:cry:
I was told that its normal by a guy who knows old school cars and that once the car gets to hot it does this.
I'm running Shell semi-synthetic 10-40.
So yeah. The other question is, nobody can actually tell me if I can go fully synthetic.
Please help a brother out.
 

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Fully synthetic is the best you can get for an engine, its only the price tag that puts me off. Check with a local Alfa garage but it shouldn't be a problem - what does non synthetic oil have that could be better for older engines ?
I notice you're in SA which means hot air and with really hot air in the engine bay already the performance will drop drastically if you can't cool your engine properly. You may want to check if you have a proper radiator for that climate. My experience with older italian cars is that they never put a proper radiator in even for Italy ... and the cars simply seemed to bog down after 20 minutes driving until I fitted better radiators (more 'alveoles' and longer cooling circuit to let the water cool down properly) and also checked that the air intake was getting air from outside and not from the engine bay.
The same problem happens on air cooled VW's in hot weather or worse, hot with high humidity levels.
Hope you can solve it coz thats a great car you have.
 

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Basically as oil temp goes up its pressure tends to go down due to changes on its density at different temperatures (higher temps turn it more liquid, lower temps turn it more heavy)

Synthetic oils work better at high temperatures since they hold their properties better but on the down side you may have oil consumption.

I'd check the oil pressure sensor. My car had the same symptoms and the oil pressure sensor was at fault. Try checking the oil pressure with a manometer (not so sure if you call it like that)

If that doesn't solve the problem you should try a higher rated oil (ie. 10-50)

If you still have trouble check the oil pump. Never had issues with it but who knows

Hope that helps, Good luck!
 

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I'm not sure about an engine as "new" as 1985, but I do know that in older engines synthetic oil can harden the seals resulting in oil leaks. Would never put anything other than mineral oil in my Duetto. I don't buy any of the "big name" oils either for any of my Alfas.
Bartoline and Comma (probably not available in SA) are both reasonably priced, high spec and very temperature tolerant, holding pressure much better than oils twice the price. They just aren't full of the many additives that are totally unnecessary if a proper maintenance schedule is followed.
 

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Discussion Starter #5
I've ahd my oil pump checked when my water pump packed up, just in case. But the thing is, I have no CLUE how to check my sensor, all I know is that it sit on the tappet cover in line with the plugs. I should maybe also add that I have Bosch T-Spark plugs in as well (if that will make a difference). I cant get anything like a 10-50 here, have looked, im considering going over to full synthetic, but like I said. Nobody can actually tell me if its going to work or make my motor break. now Lastly Black, what is this manometer your talking about? And what does it do? (besides check the sensor! lol!)
Thanks again guys for all the help...
:)
 

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A manometer is a gauge that your mechanic uses to measure oil pressure, it goes connected with a tube to a part of the oil circuit (place depends on the engine) and it shows the actual oil pressure.

Spark plugs don't make any difference on oil pressure.

On the other hand, didn't the GTV use mineral multigrade oil when it came out? That oil is "heavier" and should give a higher oil pressure. Still, i would check the oil pressure sensor. Maybe someone who knows best can point you on the right direction on where it is located (i think that it is on the carbs side of the block on my 1600 GT)

My technical vocabulary in english is rather limited unfortunately, sory if sometimes I can't get the actual word for things.

Good luck!
 

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It sounds like you have two different issues, both related to engine temperature.

As the temp goes up the oil will thin and the pressure will drop. A 10W40 semi-synthetic will act differently to the standard 20W50 that your engine is probably expecting and when hot it will be quite thin leading to a lower pressure. That isn't normally so bad as the effect is most notable at idle when you don't need huge amounts of oil pressure. Going to a full synthetic will only make it worse as then tend to be really thin (I used 0W40 Mobil One in the Jag for a while and it is like water). Also, as someone else points out, a synthetic oil may react with the existing seals opening you up to leaks. If you have completely rebuilt an engine to modern manufacturing tolerances and with new seals then I would see no problem using a synthetic oil. But for an old engine I would use a basic mineral oil. In my 68 Spider I use a specialist classic car oil, Penrite 20W60. In the Jag I use Castrol GTX high mileage 15W40.

What do you mean when you say it gets hot and feels like a VW - does the performance drop off? Does it get too hot? I'm not familiar with an 80's engine :D Does it have an ECU that perhaps has a sensor going out of spec?
 
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