Thicker oil, old engine?

bob321 · Jul 18, 2015

Hey Guys

I have a Mazda BP engine, 1.8l, 4 cylinder, DOHC with 350,000km on it. It is using quite a bit of oil, depending how hard I drive it. It uses up to 1 liter over 5000km. The normal ambient operating temperature is between 0-30 deg Celsius. The Mazda manual specifies 10w-30 (above 0 deg Celsius), I am currently using 15w-50. I’m obviously burning oil and there are also leaks, not sure how much I’m losing from either. I’m thinking about trying 15w-60. Does anyone have some advice or know a good article on the subject?

Thanks

901Memphis · Jul 18, 2015

Try some ATP 205 reseal or Liqui-moly motor oil saver

Revving2Redline · Jul 18, 2015

Maybe try a combo of liquimoly motor oil saver and liquimoly mos2. Seems moly helps free stuck rings and reduces wear. The motor oil saver is thought to be an ester than will cling to metal, extend oil changes, and reduce leaks and smoking.

Revving2Redline · Jul 18, 2015

Too thick isnt always best. If the rings have extreme carbon the mos2 and a nice highway drive could help.

Quest · Jul 18, 2015

given the mileage and the condition (oil burning even when using 15W50), a rebuild is in order.

No use nursing it with thicker oil ....it's just worn and in need of a rebuild.

Q.

19jacobob93 · Jul 18, 2015

Should be fine I wouldn't worry. I have always run 10w30 in my Falcon which is what it calls for but the manual says 40 and 50 weights are fine.
I put 20w50 in for the first time a few weeks ago and despite it knocking a bit more on cold start ups (still goes away after 10 secs) it actually runs much smoother and feels a lot better.
It never used much 10w30 during the 10k interval, maybe 0.5l, and it uses absolutely nothing at all with 40 or 50 weights

kr_bitog · Jul 18, 2015

Originally Posted By: Marco620
Maybe try a combo of liquimoly motor oil saver and liquimoly mos2. Seems moly helps free stuck rings and reduces wear. The motor oil saver is thought to be an ester than will cling to metal, extend oil changes, and reduce leaks and smoking.

My experience liquimoly motor saver is not good because I did not realize that I need to make sure the engine is clean from carbon before using motor oil saver.
When you dump motor oil saver on dirty engine, you just make it worse because the engine will be starved from oil. So it is better clean the engine and the ring first using kreen/gumout/carb cleaner through plug hole first, before you change oil and put the MOS.

SR5 · Jul 18, 2015

Hi and Welcome

Two oils you should be able to find easily are valvoline MaxLife 20w50 and Penrite HPR 30 ( 20w60).

Both these are worth a go.

I like Penrite, a good Oz company with great oils.
If ever a car or bike I have uses oil, I change to Penrite and it always uses much less oil. They always start fine in winter here, don't worry if 0 degC is your min. Temp.

Yes I like Moly Disulphide (MoS2) as a oil additive, it's the only one I use. It will certainly start fine with this in the oil, and add a bit of a safety margin if you run low on oil.

I hope it goes well for you.

Lubener · Jul 18, 2015

Originally Posted By: Quest
given the mileage and the condition (oil burning even when using 15W50), a rebuild is in order.

No use nursing it with thicker oil ....it's just worn and in need of a rebuild.

Q.

My thoughts as well. I doubt the minor change in weight will matter much. Diagnosis= excessive internal clearances.

hpb · Jul 18, 2015

An old Laser or 323 that's been to the moon and back, and it's only using a litre every 5000km? I'd say that's not a problem at all, some newer cars use that much oil! Keep doing what you're doing and don't worry about it.

19jacobob93 · Jul 18, 2015

Originally Posted By: SR5
Hi and Welcome

Two oils you should be able to find easily are valvoline MaxLife 20w50 and Penrite HPR 30 ( 20w60).

Both these are worth a go.

I like Penrite, a good Oz company with great oils.
If ever a car or bike I have uses oil, I change to Penrite and it always uses much less oil. They always start fine in winter here, don't worry if 0 degC is your min. Temp.

Yes I like Moly Disulphide (MoS2) as a oil additive, it's the only one I use. It will certainly start fine with this in the oil, and add a bit of a safety margin if you run low on oil.

I hope it goes well for you.

This.
Go for the Maxlife which is the one I use. It is an excellent oil and it has additives that prevent oil loss such as the seal conditioners which really slow or completely stop leaks from old rubber seals and O rings. Has worked great for me, stopped all the seeping parts around the engine and I now have zero oil consumption.
After my stash is used up I will be moving to Penrite HPR-10 because it is 10w50. Maxlife is 20w50 and now winter is here it's proving too thick to flow fast enough on cold mornings, the engine turns over much much slower with the 20w50 and there is a loud knock for a few seconds because the oil it too thick to flow into the furthest bearings quick enough. A 10w50 should be the best of both worlds!

Kuato · Jul 18, 2015

1L/5000km isn't very much, especially with that many km on the vehicle.

I would think it could occur just from the leaks you mentioned. In your place I would fix the leaks and then see how much it is using.

berniedd · Jul 18, 2015

1 liter every 5000 km isn't bad, considering you also have oil leaks. I'd go for the Maxlife as well.

rvt · Jul 18, 2015

I don't see anything alarming about the overall rate of consumption given the high mileage of the engine. If it were mine, I'd pull out all the spark plugs and verify they all look the same and none are getting excess oil. Once in a while an oil consuming engine will burn nearly all of it in one cylinder-which leads to misfires and other issues. If the consumption is spread out among all cylinders, I'd just keep doing what you're doing. I would not go up to 60 weight oil with that level of consumption.

Dallas69 · Jul 18, 2015

I'm not good with metric but I think using about a qt every 5k is not bad.

DeepFriar · Jul 18, 2015

Originally Posted By: hpb
An old Laser or 323 that's been to the moon and back, and it's only using a litre every 5000km? I'd say that's not a problem at all, some newer cars use that much oil! Keep doing what you're doing and don't worry about it.

+1

bob321 · Jul 18, 2015

Thanks for the replys!

Some other things I probably should have mentioned:

I checked the compression a couple of years ago (still losing oil at this point). All cylinders were a bit above the recommended compression, all about equal, compression increased a bit when oil was added.

At last oil change I added ‘liquid intelligence 230 stop leak seal expander’. I saw no oil loss after 1000km until I took it on a 600km highway drive, high load/high rpm, I lost about 0.7 liters over this trip.

I was seeing the occasional big cloud of white smoke at startup but the seal expander seems to have fixed that.

I use Shell Helix Shell Helix HX7 15w-50.

I’m a little confused as to why it loses oil after high load/rpm, given the compression is probably still ok?

Kuato · Jul 18, 2015

Originally Posted By: bob321
Thanks for the replys!

Some other things I probably should have mentioned:

I checked the compression a couple of years ago (still losing oil at this point). All cylinders were a bit above the recommended compression, all about equal, compression increased a bit when oil was added.

At last oil change I added ‘liquid intelligence 230 stop leak seal expander’. I saw no oil loss after 1000km until I took it on a 600km highway drive, high load/high rpm, I lost about 0.7 liters over this trip.

I was seeing the occasional big cloud of white smoke at startup but the seal expander seems to have fixed that.

I use Shell Helix Shell Helix HX7 15w-50.

I’m a little confused as to why it loses oil after high load/rpm, given the compression is probably still ok?

My wife's 04 Jeep Wrangler with the 2.4L uses no oil around town, but has always used about 1L per 5000km when on the highway.

rvt · Jul 18, 2015

Engines generally use more oil at high speed and load. Oil is hotter, thinner, and flying around inside engine.

Compression and oil consumption often don't go hand in hand-in either direction. Oil rings could be stuck, bearings passing more oil than new and some of winding up on cylinder walls. Intake valve guides could be leaking too much oil.

Like I posted above, usually this comes to a head when you start getting misfires due to fouled spark plugs. Doesn't sound like you're there-and often it takes a long time to get there. Just check oil and keep the level up.

SR5 · Jul 18, 2015

I had a Audi 90 that used about the same amount of oil. The mechanic wasn't worried and said it was still in spec.

I tried the Shell Helix HX7 on it, it was OK.
But on the Penrite HPR 30, it used much less oil. Penrite HPR is a great oil for older cars. Give it a go.

Thicker oil, old engine?

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