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Switch to Synthetic Oil?

M

mudpuddle

NAXJA Forum User
Location
Bristol, TN
Ok, I'v heard the stories about the switch to synthetic motor oils causing leaks in older vehicles. I have an '01 with 90K and want to switch to synthetic, but aren't too crazy about the prospect of discovering a leak. I don't presently have ANY leaks. What is everyone's experience with switching over on later model XJs?
 
mudpuddle said:
Ok, I'v heard the stories about the switch to synthetic motor oils causing leaks in older vehicles. I have an '01 with 90K and want to switch to synthetic, but aren't too crazy about the prospect of discovering a leak. I don't presently have ANY leaks. What is everyone's experience with switching over on later model XJs?
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Should not be an issue, make the change BUT keep an eye on the dipstick, the syn will start cleaning the engine out and the oil will get dirty faster, when you can't read the dipstick anymore change the filter, once the filter plugs the bypass kicks in and cycles unfiltered oil which you don't want.
 
I have an 01 and made the switch with no probs. Going to do the tranny and diffs next.

I have noticed the oil turning black fast though, only been in about 1k and it's just above being black.
 
I love the stuff and use Mobil 1 in everything I can.....BUT, my 2000 XJ just didn't like the stuff. I bought it at 116K. It was very well maintained and the inside of the engine is very clean. Right after I changed the oil it started to drip from the rear main seal. I drained out 3 quarts of the synthetic and added 3 quarts of dino oil. The oil leak stopped for the most part. Next change will receive 2 quarts synthetic and 4 quarts dino.....if it still weeps it will go back to all dino. If I keep the XJ it will probably get a new rear main seal.

I'd at least try it. Do a search on "synthetic". There's a lot of posts on it.

Good luck,
Jay in MA
 
ponyracer1 said:
I have an 01 and made the switch with no probs. Going to do the tranny and diffs next.

I have noticed the oil turning black fast though, only been in about 1k and it's just above being black.
Click to expand...

If you have the auto tranny I'd go cautious, there has been some mixed results when going syn on the AW. The results have varied between 'good' to 'destroyed' it. With syn oil generally the worst thing that can happen is leaks, tranny can have other problems.
 
RichP said:
If you have the auto tranny I'd go cautious, there has been some mixed results when going syn on the AW. The results have varied between 'good' to 'destroyed' it. With syn oil generally the worst thing that can happen is leaks, tranny can have other problems.
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x2

Do not put syn in your transmission unless it was made for it. Period. Once you start using syn in your engine I've always heard that you're not supposed to go back to regular oil either. I run mobil 1 in my yota and love the stuff...I still change it every 3000 miles and it's the same color as the day I poured it in. My father runs shaffer oil in his work trucks and likes it. It's a parrafin wax based oil, other than that I don't know much about it though other than the fact it was designed for use in the big rig industry.
 
Last edited:
...I still change it every 3000 miles and it's the same color as the day I poured it in.
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Thats not good, the color change with any oil is dirt that it cleaned and gathered from the engine.

Non-detergent motor oil also is also clear between oil changes.
 
 
I use synthetic; Amsoil in everything including the AW4 for about 75,000 miles. Bought the XJ at 135,00 and switched at my first oil change. My only pproblem was oil leaks from the 4.0 for some 20,00 miles then they all went away except the front of the engine. I have no problem whatsoever with anything. I will not go back to Dino juice.
 
I thiink you would be better off making your own blend.

From the article at http://www.boss302.com/oil.htm

"Let's see...blended oils.

The oil companies found out that by adding a small amount of synthetic base stock to conventional 'dino' stock, they were able to significantly increase its cold and hot temperature performance. It approaches full-synthetic performance, but is still a ways away. (Blended oils are almost a definite with GF-4/5 oils). They are significantly better than regular 'dino'. However, there are still the trace elements in the 'dino' portion of the oil, and that is what contributes to sludge formation. For that reason, I do not use blended oils. Blended oils use anywhere from 2% to 5% synthetic base, depending on viscosity and brand. None are higher than 5%. (Most erroneously assume it is 50/50). This is a BIG moneymaker for the oil companies."
 
Mobil one is not a true synthetic oil it is dino based oil , there are only a couple true syn. on the market Amsoil Royal Purple and the jury is still out on Red Line . And syntheic do not cause leaks and you can mix oils but not recommended . Also changing a trans to syn. oil will not cause it to go out you have to make sure you put the right oil in , also the worst thing you can do to a trans that has never been cared for is to start caring late in its life . You will pay for a good oil but you also increase change times it figures the same in the end Amsoil offers an oil you can change once a year or 25000 miles just change filter at 4000 or 5000 . If you where to put a good filter system on you wouldn't really have to change just filters and send a sample every 7500 miles don't change till they tell you too .
 
PolishX said:
what about a blend . like the Quaker state stuff
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I've threatned to shoot anybody who brings quacker state or pennz on the property.
You could mix your own in a 50/50 mix, I'd stay brand same thiough, like mobil dino and mobil-1 or castrol and castrol syntec. More than a couple of times I've had to add a quart of normal oil to my Mobil-1.
 
Jay Welch said:
I love the stuff and use Mobil 1 in everything I can.....BUT, my 2000 XJ just didn't like the stuff. I bought it at 116K. It was very well maintained and the inside of the engine is very clean. Right after I changed the oil it started to drip from the rear main seal. I drained out 3 quarts of the synthetic and added 3 quarts of dino oil. The oil leak stopped for the most part. Next change will receive 2 quarts synthetic and 4 quarts dino.....if it still weeps it will go back to all dino. If I keep the XJ it will probably get a new rear main seal.

I'd at least try it. Do a search on "synthetic". There's a lot of posts on it.

Good luck,
Jay in MA
Click to expand...


Same thing happened in my 00'. Made the switch to synthetic, and a day later my rear main seal started leaking. A month later, most of my gaskets started seeping. Went back to old fashioned 76 oil and gaskets quit seeping and rear main seal quit leaking as much.
 
Well, I can't comment on the whole leak issue as before I grenaded my old engine last November I used Mobil 5000 (was Mobil 'Drive Clean' then) 10W30.

After the build-up on my new engine and the increased tolerances for longer life (I play hard :) ) I've been using Mobil 1 15W50 (after proper break-in of course). However, my local NAPA had a sale last time I did and oil change on Royal Purple 20W50, so I figured 'why not'. I tell you, I won't be going back to Mobil 1. There may be a big cost difference from Royal Purple to well, anything else, but my heavy lift tick (performance cam) has greatly reduced and it seems to idle somewhat smoother. I figure if I spent that kinda cash building up a nice engine, why not treat it to the good Royal Purple and a K&N Filter? On an older engine, I'd probably run just regular Dino Oil...
 
That's good to know. I didn't know NAPA sold the Royal Purple product.....good stuff. Do you know if the entire product line is available through them?

RCman said:
.......... However, my local NAPA had a sale last time I did and oil change on Royal Purple 20W50, so I figured 'why not'.
Click to expand...
 
A few years ago almost every fleet owner in the US jumped on the syn band wagon.
The promise was less maintenance and longer life, and in many cases free oil for their endorsement.
These days only the ones that get it free still use it.

The internal combustion engine running on Gas or Diesel is a very dirty piece of equipment.

Filtration can't remove the chemicals that cause the most problems so you still need to do regular oil changes at 3000 or 5000 miles, even for warranty coverage so it don't make any difference if you use $6.00 a quart syn or quality Dino as long as you change it.

Now having said that using syn in other parts of the vehicle does make sense.
 
Jay Welch said:
That's good to know. I didn't know NAPA sold the Royal Purple product.....good stuff. Do you know if the entire product line is available through them?
Click to expand...

Just called my local NAPA to ask and they said they could get anything in the product line (inculding apparel and stickers) with 2 days notice. However, the stuff ain't cheap so it might be better to get it online and pay shipping depending on what your lookng for.

langer1 said:
Filtration can't remove the chemicals that cause the most problems so you still need to do regular oil changes at 3000 or 5000 miles, even for warranty coverage so it don't make any difference if you use $6.00 a quart syn or quality Dino as long as you change it.
Click to expand...

Agree 100%. I don't think I'd ever get myself to change my oil at anything more than 3000-5000 even when I pay top dollar for it. However a good filter goes along way, but thats another topic!
 
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