Low Oil Viscosity Causing Lifter Noise?

[Phishin]

My 1990 Chevy truck with a 350TBI (170k miles) in it has recently developed a lifter/valve chatter at start up. I'm currently running M1 10w40 HM with a heavy dose of MMO (20-25%)to try to clean up the sludge/crud from the PO.

Do you think the MMO has thinned the M1 out too far, causing a low oil pressure and thus causing the valve chatter?

What has me convinced that this might be the case is, when I start the truck in the morning (cold engine, about 65 degrees outside), about half the time the lifter is ticking. And if it does, it goes away quickly in 10-30 seconds of idling.

However, if the truck is warmed up from driving (there is never a tick), but I shut it off and restart it 2-20 mintues later, the tick is at it's loudest and goes away much more slowly.

So, the hot oil (which is now thinner) is having a harder time pumping up the lifter. Is this a solid theory?

I want to keep this cleaner oil in for a bit longer and I will change to MMO free M1 15w40 HDEO. Do you think this will fix my chatter?

Should I swap it out now? It's only been in for about 1500 miles.

 

[MichiganMadMan]

Not sure I would point to the "low" oil viscosity over 170K miles of neglect and abuse as the root cause. I had a similar engine in a Roadmonster from the same era, and I had to adjust the rocker arms every once and a while or I would get a lifter tick. Got rid of it with 225,000 miles ran great, everything else was falling apart.
I'd have a look at the rocker arm lash and see if it get's better after that. I also think that the trucks didn't got roller cam until later in the 90's so you might want to use an oil with relatively high ZDDP.
Good luck,
MMM

 

[addyguy]

The MMO, i'd guess, is cleaning varnish/sludge off the valvetrain, and the clearances have 'opened up' a bit, resulting in noise.

Does the engine run well otherwise?

 

[LeakySeals]

MMO is approx the weight of a straight "3" (according to various posts). That M1 HM had far superior cleaning power to the 1930's naphtha in MMO. I think its just a bad combo, little too much MMO. If you have no leaks, try Shell Rotella T6 synthetic 5w40. Plenty of cleaners, high levels of zzdp. Like putting a blanket over it, really quiet. Available at walmart, $21 a gal.

 

[KCJeep]

I tried a run of 25% MMO for some heavy cleaning and had the same problem, death rattle at start up although I did this during December and it was truly cold which aggravated the problem.

The thing I believe I learned is that although MMO is thin, it is basically a straight 5w oil with very low VI. Since I used a very thick low VI base oil (15w40 to offset the thinning of the MMO) I pretty much ended up with a thinnish SAE 30 weight oil and thus the clatter at frigid cold start up.

Man it did clean though, things got real black in just a couple hundred miles but I had to dump it I couldn't take 60 seconds of death rattle. A fill of PYB 5w30 instead and it disappeared.

So...while I still clean with MMO I now take the slow and steady approach, I consider 10-15% about ideal and I try to couple it with a high VI base oil.

 

[bourne]

Are you using a different oil filter this round ? and yes MMO is more like a 5-10 weight oil. 10w30 T5 or 5w40 T6 would be ideal in this situation.

 

[mechtech2]

Sounds normal for worn parts.
A simple lifter adjustment is also a possibility.
Jillions of Chevys have some lifter tick.

1,500 miles is a long time for a heavy dose of MMO.

 

[abycat]

Originally Posted By: mechtech2
Sounds normal for worn parts.
A simple lifter adjustment is also a possibility.
Jillions of Chevys have some lifter tick.

1,500 miles is a long time for a heavy dose of MMO.


Yeah worn lifters for sure. They are hydraulic and are only torqued down to an only setting. The nuts bottom out on the studs so over tightening wont help.

Im pretty sure the hyd part bleeds out oil more and faster than when new so they dont have the proper height and absoarbtion capability. Just think you could put a new cam set in it and be done with it for under 500$. Would really wake it up.

 

[Phishin]

Originally Posted By: bourne
Are you using a different oil filter this round ? and yes MMO is more like a 5-10 weight oil. 10w30 T5 or 5w40 T6 would be ideal in this situation.


Yes, I change the oil filter every 500 miles with a Purolater.

and for the guy who just posted above, no, this truck doesn't have hydraulic valve train...I don't think. It's old school.

Is the rattle causing damage or is it just annoying? I just changed the oil filter when it was a quart low, and lost a quart in changing the filter, so it has a fresh 2 quarts of 10w40 HM in it now.

Okay, I'll change out the oil this weekend and see what happens. Probably go with T6 or the M1 HDEO. No MMO!!

 

[WMSmotorhead]

Although I don't hate MMO, I wouldn't feel the least bit confident running that concentration. I've sort of given up the idea of any Leave-In engine bath.

I'd say fresh un-tainted oil of good quality, and checking all adjustments would be the ticket.

 

[440Magnum]

In my experience, sudden lifter noise is almost always due to the check valve inside the affected lifter(s) getting a bit of crud stuck in it. That large a dose of MMO stands a good chance of unleashing a lot of crud to clog lifter mechansisms. Get back to unadulterated oil, fresh filter, and see how it does. The lifters may eventually spit out the stuff that's making them noisy and work fine after that.

 

[OVERKILL]

Originally Posted By: WMSmotorhead
Although I don't hate MMO, I wouldn't feel the least bit confident running that concentration. I've sort of given up the idea of any Leave-In engine bath.

I'd say fresh un-tainted oil of good quality, and checking all adjustments would be the ticket.


This.

25% light bright stock and stoddard solvent isn't a recipe for longevity here folks. I fail to see what is so wrong with letting a good oil clean up this type of mess rather than trying to "solvent it to death" and risk wiping a bearing (or several).

 

[abycat]

Originally Posted By: Phishin
Originally Posted By: bourne
Are you using a different oil filter this round ? and yes MMO is more like a 5-10 weight oil. 10w30 T5 or 5w40 T6 would be ideal in this situation.


Yes, I change the oil filter every 500 miles with a Purolater.

and for the guy who just posted above, no, this truck doesn't have hydraulic valve train...I don't think. It's old school.

Is the rattle causing damage or is it just annoying? I just changed the oil filter when it was a quart low, and lost a quart in changing the filter, so it has a fresh 2 quarts of 10w40 HM in it now.

Okay, I'll change out the oil this weekend and see what happens. Probably go with T6 or the M1 HDEO. No MMO!!



My dads 1990 has hyd lifters. Yours should too.

 

[LeakySeals]

I'm a long time user of M1 and I don't think M1 any flavor is a good choice for older engines with mechanical ticks. M1 does seem amplify mechanical engine noise for mysterious reasons. Ticking because its sludgy or sticky is a different story. M1 works well cleaning in those cases and quiets them down.

 

[TFB1]

I'm of the opinion dumping a load of MM into M1 is ruining perfectly good oil... The M1 by it's self would do a great job of cleaning if only given some time...

 

[OVERKILL]

Originally Posted By: TFB1
I'm of the opinion dumping a load of MM into M1 is ruining perfectly good oil... The M1 by it's self would do a great job of cleaning if only given some time...


Exactly.

 

[jjcom]

If it were my vehicle, I'd probably run Rotella T6 with a good filter for 3-5k miles. When it comes due for an oil change, I'd throw a can of seafoam in the oil, let it idle for 20 minutes or so. Change and repeat a couple times.

 

[Phishin]

Originally Posted By: OVERK1LL
Originally Posted By: TFB1
I'm of the opinion dumping a load of MM into M1 is ruining perfectly good oil... The M1 by it's self would do a great job of cleaning if only given some time...


Exactly.


I had the M1 HM in it for about 2000 miles. Oil looked about the same. Poured in a quart of MM0. Turned dark in 300 miles. When it was low a quart again, I threw in a half quart of MMO and a half quart of M1 HM. I've done that twice.

I'll just dump the oil and refill with T6 15w40. And knock off the MMO treatments. But it sure did knock some junk loose.

I've changed 4 oil filters so far. Each of them I cut open and the first one was pretty packed. The second one I cut open after 250 miles, it was a lot better. The third and fourth just had a good amount of crusty crud in the filter fold valleys.

I think it's about done.

 

[OVERKILL]

Originally Posted By: Phishin
Originally Posted By: OVERK1LL
Originally Posted By: TFB1
I'm of the opinion dumping a load of MM into M1 is ruining perfectly good oil... The M1 by it's self would do a great job of cleaning if only given some time...


Exactly.


I had the M1 HM in it for about 2000 miles. Oil looked about the same. Poured in a quart of MM0. Turned dark in 300 miles. When it was low a quart again, I threw in a half quart of MMO and a half quart of M1 HM. I've done that twice.

I'll just dump the oil and refill with T6 15w40. And knock off the MMO treatments. But it sure did knock some junk loose.

I've changed 4 oil filters so far. Each of them I cut open and the first one was pretty packed. The second one I cut open after 250 miles, it was a lot better. The third and fourth just had a good amount of crusty crud in the filter fold valleys.

I think it's about done.


Colour doesn't mean much. The reaction of bright stock and stoddard solvent to heat may darken the lubricant by itself.

 

[LeakySeals]

Originally Posted By: OVERK1LL
Originally Posted By: Phishin
Originally Posted By: OVERK1LL
Originally Posted By: TFB1
I'm of the opinion dumping a load of MM into M1 is ruining perfectly good oil... The M1 by it's self would do a great job of cleaning if only given some time...


Exactly.


I had the M1 HM in it for about 2000 miles. Oil looked about the same. Poured in a quart of MM0. Turned dark in 300 miles. When it was low a quart again, I threw in a half quart of MMO and a half quart of M1 HM. I've done that twice.

I'll just dump the oil and refill with T6 15w40. And knock off the MMO treatments. But it sure did knock some junk loose.

I've changed 4 oil filters so far. Each of them I cut open and the first one was pretty packed. The second one I cut open after 250 miles, it was a lot better. The third and fourth just had a good amount of crusty crud in the filter fold valleys.

I think it's about done.


Colour doesn't mean much. The reaction of bright stock and stoddard solvent to heat may darken the lubricant by itself.

Where you getting stoddard add from. Is that the Pale oil?