pug 306 engine oil

[jarrus]

what oil is good for a 1998 1.9 turbo diesel (xudt)?

i use castrol edge 5w-40 but i have been told it's overpriced and not that great so I was thinking of switching,

also what about the 2.0 hdi and the gti6 that is in the 306 as well?

 

[HDi fun]

Fully synthetic low-sulphated-ash formulations only if the car has a DPF. API CH-4 or higher. Petrol engines don't have or need DPFs, the XUDs were never fitted with them and the 2.0 HDi 90/100 also, AFAIK was never fitted. The later 2.0 HDi 136 and 1.6 HDi 110 (both designated FAP) are fitted with these devices.

The XUDT is less demanding of its oil but in my opinion you can never have an oil that's TOO good.

I ran my 2.2 HDi on Millers diesel specific synthetic for a couple of years and then switched to AMSOIL DEO. But it's very pricey.

With the XUDT if you are sensible by getting the stuff changed at regular intervals a good quality 10w/40 will work well. Halford's oils are, I'm told, made by Exxon/Sprint (Esso). They do a diesel specific one which will have extra detergency in its additive pack.

However, let's see what Guy of Opie Oils has to say. He's the guru; his advice is liquid gold.

 

[oilman]

Castrol Edge TD is actually a really good oil. No, it's not cheap, but in comparison to some similar oils, it's a bargain.

For all the engines that you mention a 5w-40 synthetic is the optimum choice.

http://www.opieoils.co.uk/c-656-5w-40.aspx

Out of those, the best ones are the Fuchs/Silkolene Pro S, Motul 300V, Redline and Gulf Competition. The Motul 8100 X-Cess, Gulf Formula G, Fuchs Supersyn and Mobil Synt S are good, cheaper alternatives.



As a budget choice, a 10w-40 will be fine and I would either go for the Fuchs XTR, Millers XSS or Motul 6100



http://www.opieoils.co.uk/c-657-10w-40.aspx

With oils like the Halfords own brand, being made by a certain manufacturer is no bonus at all. Although Esso may make the Halfords stuff (apparantly Castrol and Comma make oils for them too), having a well known oil brand associated with them is no advantage, it certainly isn't a rebranded premium product. The own brand oils are made to a budget and specifically aimed to meet certain specifications, whereas the brand name ones are made to meet an exceed an array of specs. For example, Halfords own VW oil meets the VW505.01 spec, and some other lower specs. Castrol Edge TD (originally made to meet the VW 505.01 spec) also meets the BMW LL04 and Merc 229.51 specs, both a lot harder to achieve than the VW505.01, so the oil has to be a higher spec and will mean that it gives better protection.

Cheers

Tim

 

[HDi fun]

That's your definitive answer!

 

[jarrus]

Looks all good, so which of those top spec synthetic oils are suitable for the diesels in the list i wrote?

I thought about using the 15w-40 that redline have in my xudt, that fully synthetic,

cheers

 

[HDi fun]

15w/40 is going to give poorer startup (cold) protection that a 10w or 5w.

 

[oilman]

Looks all good, so which of those top spec synthetic oils are suitable for the diesels in the list i wrote?

I thought about using the 15w-40 that redline have in my xudt, that fully synthetic,

cheers

The ones I mentioned are all suitable for diesel. There is no such things as a diesel specific oil (despite what the labels say). Some meet diesel specifications (like VW, BMW, Merc or ACEA C specs), but they are also fine in petrol engines. As the engines you mentioned don't have manufacturer or ACEA C specs to meet, they are fine with oils of the right grade, so all of the ones I mentioned are fine.

If an oil is called something like 5w-40 Turbo Diesel or 15w-40 diesel, it's just to give the customer confidence that the oil is suitable for diesel engines.

15w-40 is just sacrificing cold start protection for a name on the label. Go for the 5w-40 or 10w-40 Redline if you want a very good oil.

Cheers

Tim

 

[HDi fun]

One other thing to add regarding SAE gradings is that a cheap 5w/40 is less likely to stay in grade for as long as a better quality one. Reason being that the cheaper oil will use less stable base stocks which means more viscosity modifiers in the additive pack.

So, don't buy a cheap synthetic 0w/60, for example, the wide operating range will not last as long as a quality synthetic 5w/40.

 

[oilman]

Very true.

 

[jarrus]

Thanks for the heads up, I didn't know that there wasn't a diesel specific oil, so as long as the grade is fine then that the stuff to use

 

[jarrus]

and also, yeah having a reliable engine is probably down to a good quality oil, probably why mind as lasted well

 

[HDi fun]

There are some diesel specific oils but whether they're superior to ones that suit both technologies is questionable. I used to use AMSOIL DEO, diesel specific 5w/40 full synthetic.

API rating CJ4 yet it had an API SM rating as well! What does that tell us?

 

[jarrus]

I did look at some redline water wetter as well,

do you use this as an anti freeze substitute?

my current mix is 50/50 (50% water and 50% antifreeze)

 

[HDi fun]

I did look at some redline water wetter as well,

do you use this as an anti freeze substitute?

my current mix is 50/50 (50% water and 50% antifreeze)

Your car probably has long life OAT coolant. I think this is incompatible with Water Wetter and Purple Ice.

 

[oilman]

There are some diesel specific oils but whether they're superior to ones that suit both technologies is questionable. I used to use AMSOIL DEO, diesel specific 5w/40 full synthetic.

API rating CJ4 yet it had an API SM rating as well! What does that tell us?

They are fine for normal petrol and diesel engines. For example, that DEO meets a Merc spec that can be applied to diesel or petrol engines.

 

[oilman]

I did look at some redline water wetter as well,

do you use this as an anti freeze substitute?

my current mix is 50/50 (50% water and 50% antifreeze)

Unless you are getting excessively high water temps, I wouldn't bother with Waterwetter, Mocool etc. A decent antifreeze is the best thing for the car.

You can mix the Waterwetter with other coolants without any problems

 

[HDi fun]

They are fine for normal petrol and diesel engines. For example, that DEO meets a Merc spec that can be applied to diesel or petrol engines.

That's what I thought, too. It was meant to be a rhetorical question .

On this note, please would you tell me which spec denotes DPF compatibility, which, I think, is a low or zero suphated ash content?

Would Water-Wetter or other similar surface tension reducing additive be of benefit in increasing the efficiency of an oil/water heat exchanger?

Enough questions...sorry

 

[jarrus]

It's as i thought, I get really low water temps 75 degrees Celsius is normal operating temp,
and if it goes above 90 i got 2 big cooling fans on the rad and the temp soon drops, I suppose the biggest concern for me is heat soak in the intercooler as it is sited on top of the engine, but I might rectify that once I have a job...

 

[HDi fun]

It's as i thought, I get really low water temps 75 degrees Celsius is normal operating temp,
and if it goes above 90 i got 2 big cooling fans on the rad and the temp soon drops, I suppose the biggest concern for me is heat soak in the intercooler as it is sited on top of the engine, but I might rectify that once I have a job...

75-90 is quite low enough. Below that would be less than ideal.

as for the intercooler's location I'm not sure what to do about that. A bonnet vent would be helpful if you fancy some cutting.

 

[oilman]

That's what I thought, too. It was meant to be a rhetorical question .

On this note, please would you tell me which spec denotes DPF compatibility, which, I think, is a low or zero suphated ash content?

Would Water-Wetter or other similar surface tension reducing additive be of benefit in increasing the efficiency of an oil/water heat exchanger?

Enough questions...sorry

I think it would increase the efficiency in heat exchange, it makes sense, but no ones asked me that before and the person I would like to ask is on holiday.

If you follow this link, part way down the page is a table of the API specs and what they mean

http://www.carbibles.com/engineoil_bible.html

ACEA C specs are low ash

 

[jarrus]

I will read that properly when I get the chance, it looks rather interesting and has told me a lot of things I didn't know, but something I do know is oil choice is key, so why do they talk about oil specifically for diesels? I thought it wasn't necessary,

 

[HDi fun]

I will read that properly when I get the chance, it looks rather interesting and has told me a lot of things I didn't know, but something I do know is oil choice is key, so why do they talk about oil specifically for diesels? I thought it wasn't necessary,

Diesel specific oils will have extra detergents in the additive pack to deal with the higher levels of soot etc. The object is to keep the soot particles in suspension and therefore supposedly out of where they could harm the engine. Yet there are many oils out there which are perfectly good for both diesel and petrol applications.

Your XUD-T is not a difficult engine insofar as it's not running insane boost pressures and it doesn't have a particle filter so a decent 10w/40 semi-synthetic will be a good safe choice.

A fully synthetic will always be superior and will stand up to longer drain intervals but I'd take some precautions when switching to synthetic. It would be a good idea to flush the engine first so that any contaminants left in are dispersed and removed. Synthetic oils are extremely effective at removing years old deposits so you want these out BEFORE filling with the new oil.

Also, if you do go down the synthetic route it would be unwise to revert to semi's subsequently.

I also advise that you stick with one oil for filling and topping up.

SO if you choose Motul Oil 'X', then stick with Motul Oil 'X' for topping up.

Mixing synthetics can be a problem. The base stocks come in two flavours:-

Poly alpha olefins and polyolesters. These are not mutually compatible.

In my opinion some of AMSOIL's products still sit amongst the best on the market but Opieoils will have access to later and more accurate information.

 

[oilman]

Modern oils all have sufficient detergent levels to be suitable for diesel and petrol, except possibly in the bog standard motor factor stuff I guess.

There is no need to flush the engine and flushing can be harmful. What can happen is the flush can loosen harmless deposits in the engine, but then not remove them. Your new oil goes in and after it gets warm and is flowing nicely, the bits which are loosened come off into the oil, so you end up with hard bits floating around in your oil - the last thing you want. If you really want to flush the oil system, the best thing you can do is drain out the oil that is in there, put in some cheap (the cheapest you can find) mineral oil (perhaps add a small amount of good oil to get better detergency)and run the car for 15 minutes to an hour so the oil gets nice and warm. After running it, drain out the mineral oil and put in the correct oil.

No need to stick to one oil for the fill and one for top ups. All oils mix (except Castor based ones) you can even use a top end ester oil for the fill and top up with basic mineral stuff. Only problem is that you dilute the quality of the good oil. You can mix PAO and ester oils, in fact the top end ester oils are a mix of ester and PAO, some even have a drop of hydrocracked mineral oil

 

[HDi fun]

Modern oils all have sufficient detergent levels to be suitable for diesel and petrol, except possibly in the bog standard motor factor stuff I guess.

There is no need to flush the engine and flushing can be harmful. What can happen is the flush can loosen harmless deposits in the engine, but then not remove them. Your new oil goes in and after it gets warm and is flowing nicely, the bits which are loosened come off into the oil, so you end up with hard bits floating around in your oil - the last thing you want. If you really want to flush the oil system, the best thing you can do is drain out the oil that is in there, put in some cheap (the cheapest you can find) mineral oil (perhaps add a small amount of good oil to get better detergency)and run the car for 15 minutes to an hour so the oil gets nice and warm. After running it, drain out the mineral oil and put in the correct oil.

No need to stick to one oil for the fill and one for top ups. All oils mix (except Castor based ones) you can even use a top end ester oil for the fill and top up with basic mineral stuff. Only problem is that you dilute the quality of the good oil. You can mix PAO and ester oils, in fact the top end ester oils are a mix of ester and PAO, some even have a drop of hydrocracked mineral oil

I agree with all you say, and thankyou for clarifying this. I honestly thought that PAOs and polyolesters were totally incompatible. One further question (yes, another one :embarrest:, I'm sorry):

You mention sufficient detergency. But do some diesel specifics go beyond what is sufficient perhaps? Or is more than enough actually too much?

 

[oilman]

The problem with a lot of the information about oils is that a lot of it is either out of date or just wrong and if you see it from a so-called reputable source there is no reason not to believe it. With our information there is a guarantee in that we've been doing this for quite a while now and we'd have been sued out of business if our information had caused engine failures etc.

Detergents are part of the additive pack so they are there to meet the requirements of the oil. Cheap oils have the minimum additive pack necessary, so the minimum acceptable detergency, but long life oils have a higher content as they get used over the lifetime of the oil. The only issue I can think of with detergency is that you need a balance in the additives as you would need to balance the detergents out with anti-foaming agents

 

[zed head]

this is a question everyone has a opinion on. some right ,some wrong, and some not based on fact or uneducated knowledge.

check out things for yourself, just because someone tells you that the oil your using is bad or not suitable, what basis is there advise given.

if you buy the best oil you can afford based on the manufactures specs you cant go far wrong. if you want better performance from your motor, and its a high performance car then expect to pay 75 to 150 for some of the best oils. you have to figure out if it is worth it to you or not. drive hard drive safe. zed head.

 

[oilman]

Very true Zed Head.

Cheers

Guy

 

[HDi fun]

THe old adage. You generally get what you pay for. Sometimes you get very good value for money indeed.

But you can also overpay for a poor product.

I've been keen on Amsoil's DEO 5w/40 for a while. Previously I used Millers 5w/40 fully synthetic diesel engine oil.

It seemed fine but the switch to Amsoil did see engine oil temperatures drop by between 5 and 10 degrees (C) so I have to assume that it had a better specific heat capacity.

In the old Seat we have at the moment I just use Halfords 10w/40 semi synthetic diesel oil. But that car really does not put any great demands upon its oil other than to hold soot in suspension for a reasonable period between changes.

It's not even turbocharged so there's little heat to deal with compared to a car with forced induction.

 

[jarrus]

I think maybe then we need to sticky this thread because there's a lot of useful information in here that is useful to everyone,