Strange cold start knock situation

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19jacobob93

19jacobob93

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Feb 12, 2014
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Gold Coast, QL, Australia
So I've been running 10w30 in my car and on colder mornings I had a slight knocking noise that was in time with, but separate from a slight lifter tick, and would go away after about 30 seconds to a minute. It was intermittent and didn't do it evey morning.
I had a few people recommend running a thicker oil but I said no because it only happens when the engine is stone cold (left over night and in winter only) therefore when the oil is at its thickest. When the engine is warm or has been sitting for just a few hours, start ups are silent.
Anyway it continued so I thought hey why not just try a thicker oil as I have some 50 weights lying around. I went for Maxlife 20w50 which I thought would be fine since we rarely even reach freezing point here on the coast.
Well, the morning after the dull knocking noise was now a loud tapping noise and it didn't sound good! Still does it most mornings and even today after work!
Yet again once its warmed up it runs perfectly smooth and silent! Even with the 10w30 in traffic with the a/c on in the midsummer heat it would still be nice and quiet, no knocks or low oil pressure so I don't think it is a work main or rod bearing.

Only thing I can think of is a dying oil pump, being a big I6 with a long crank, the oil pump has to pump that oil a long way to those last bearings! I'm thinking it's not pumping as fast as it should be which is starving the last bearing(s) of oil on start up and the thicker oil made it harder still to pump it out (engine turns over much slower too with the thicker stuff)

What do you guys think?
Cheers
 
Originally Posted By: Char Baby
Have you tried a thinner oil instead of the 20W50 or 10W30?
Maybe try a 5W**!

I haven't and it would probably help but this engine was back specced to 10w30 from 5w30! I might try a 5w40 but they are all in the next price bracket up! Most 5w40s cost twice as much and more than the $25-30 I paid for the Durablend and Maxlife here
 
I had the same problem with a Toyota truck just after I changed the oil and filter. I used a Fram filter and 10 w 30 dino. On cool mornings ( 40 degrees F ) the lifters would clatter like mad. Changing to a Toyota factory filter cured the problem. I suspect the Fram does not bypass as quickly as a factory filter. I thought that dirty oil is better than no oil and never used anything but factory filters after that.
 
I just *knew* this was one of our Aussie BITOG members ... Checked ... Yep.

Okay, not sure of the details of your motor or what kind of oil-regulated system you might have (like Variable Valve Timing) but it works like this .... If a heavier viscosity oil makes it worse, most of us would switch to a lighter viscosity oil.

And if it's a cold-start only issue, most of us would try a lower viscosity W-graded oil (like 5w-40 instead of 10W-40). I know it gets cold and hot Down Under, just use a W-rated oil that doesn't knock and is graded high enough to handle your ambient +40C (or whatever you expect to see where you drive in Oz.
 
Originally Posted By: 19jacobob93
Originally Posted By: Char Baby
Have you tried a thinner oil instead of the 20W50 or 10W30?
Maybe try a 5W**!

I haven't and it would probably help but this engine was back specced to 10w30 from 5w30! I might try a 5w40 but they are all in the next price bracket up! Most 5w40s cost twice as much and more than the $25-30 I paid for the Durablend and Maxlife here


How about trying(or going back to) the 5W30 which should be the same price as your current 10W30? It seems as though you're staying with conventional motor oils, which should be more than satisfactory as some synthetic oils can often make the noise(s) worst. Though the Syn oils overall are better!

I guess that a 5W anything, is what I am getting at! And indeed, try another oil filter brand for your application as there juuuuust may be some differences!
smile.gif


And, for experimental purposes, you may(may not) want to try a 0W oil? IDK!
 
Last edited:
Hey OP,
I thought you went with the MaxLife 20w-50 to control a few oil leaks, how is that going?

If no better, go back to the lighter oils.

If it is helping then you are caught between a rock and a hard place. Not for everybody, but I added a dose of Moly Disulphide ( MoS2 ) to my old Holden Kingwood when the only common oil was 20w-50. It made a big difference to starting on a cold winter morning. Only problem is by the time you factor this cost in you could probably buy a cheaper synthetic. However maybe a Dino stops oil leaks better.

Just an idea.
 
Friend of mine has a 1990 Jeep Cherokee with a very bad head gasket leak. When it gets up to temp, it just pours out. We decided to throw some 20w-50 in it. It didn't slow down the oil leak but, wow, that thing makes a LOT of noise until it's up to temperature.
 
Originally Posted By: 19jacobob93


Only thing I can think of is a dying oil pump, being a big I6 with a long crank, the oil pump has to pump that oil a long way to those last bearings! I'm thinking it's not pumping as fast as it should be which is starving the last bearing(s) of oil on start up and the thicker oil made it harder still to pump it out (engine turns over much slower too with the thicker stuff)

What do you guys think?
Cheers


Really?? You think a oil pump can measure distance?? It could care less...

If pressure exceeds relief valve setting(which is usually the case on cold start) the thicker the oil, the more that's bypassed back in to the pan and not into the engine... Also the thicker oil has more resistance to flow(sort of drags vs flows smoothly through the oil galleys), thus takes longer to reach the extremes of the engine...

A lighter oil would probably help(0/5W-30), but there are no guarantees... Still switching to thicker oil was absolutely the wrong direction to go... It's just the nature of worn lifters & bearings to be noisy on startup...
 
Originally Posted By: TFB1
Originally Posted By: 19jacobob93


Only thing I can think of is a dying oil pump, being a big I6 with a long crank, the oil pump has to pump that oil a long way to those last bearings! I'm thinking it's not pumping as fast as it should be which is starving the last bearing(s) of oil on start up and the thicker oil made it harder still to pump it out (engine turns over much slower too with the thicker stuff)

What do you guys think?
Cheers


Really?? You think a oil pump can measure distance?? It could care less...

If pressure exceeds relief valve setting(which is usually the case on cold start) the thicker the oil, the more that's bypassed back in to the pan and not into the engine... Also the thicker oil has more resistance to flow(sort of drags vs flows smoothly through the oil galleys), thus takes longer to reach the extremes of the engine...

A lighter oil would probably help(0/5W-30), but there are no guarantees... Still switching to thicker oil was absolutely the wrong direction to go... It's just the nature of worn lifters & bearings to be noisy on startup...
I think a 5W 40 is worth trying, something like T6, but I am curious as to why Ford changed their recomendation to 10w 30 from 5w 30.
 
Last edited:
Originally Posted By: TFB1
Originally Posted By: 19jacobob93


Only thing I can think of is a dying oil pump, being a big I6 with a long crank, the oil pump has to pump that oil a long way to those last bearings! I'm thinking it's not pumping as fast as it should be which is starving the last bearing(s) of oil on start up and the thicker oil made it harder still to pump it out (engine turns over much slower too with the thicker stuff)

What do you guys think?
Cheers


Really?? You think a oil pump can measure distance?? It could care less...

If pressure exceeds relief valve setting(which is usually the case on cold start) the thicker the oil, the more that's bypassed back in to the pan and not into the engine... Also the thicker oil has more resistance to flow(sort of drags vs flows smoothly through the oil galleys), thus takes longer to reach the extremes of the engine...

A lighter oil would probably help(0/5W-30), but there are no guarantees... Still switching to thicker oil was absolutely the wrong direction to go... It's just the nature of worn lifters & bearings to be noisy on startup...

Should be pretty common sense that a thicker oil takes longer to be pumped over a certain distance than a thin oil... But yeah going thicker proved it wasn't a clearance issue but an oil delivery/supply issue and I'm pointing my finger at the oil pump because they are what delivers/supplies the oil to the components.
 
Originally Posted By: HerrStig
Originally Posted By: TFB1
Originally Posted By: 19jacobob93


Only thing I can think of is a dying oil pump, being a big I6 with a long crank, the oil pump has to pump that oil a long way to those last bearings! I'm thinking it's not pumping as fast as it should be which is starving the last bearing(s) of oil on start up and the thicker oil made it harder still to pump it out (engine turns over much slower too with the thicker stuff)

What do you guys think?
Cheers


Really?? You think a oil pump can measure distance?? It could care less...

If pressure exceeds relief valve setting(which is usually the case on cold start) the thicker the oil, the more that's bypassed back in to the pan and not into the engine... Also the thicker oil has more resistance to flow(sort of drags vs flows smoothly through the oil galleys), thus takes longer to reach the extremes of the engine...

A lighter oil would probably help(0/5W-30), but there are no guarantees... Still switching to thicker oil was absolutely the wrong direction to go... It's just the nature of worn lifters & bearings to be noisy on startup...
I think a 5W 40 is worth trying, something like T6, but I am curious as to why Ford changed their recomendation to 10w 30 from 5w 30.

I think it was because they introduced a 15,000km service interval with 5w30 back in 1998, back in the 90s most 5w30s were breaking down/shearing out of spec way before 15k and damaging engines. 10w30s are, or at least were much more robust
 
Originally Posted By: 4wheeldog
I remember when you posted a video of that noise. It did not sound internal to me, and I still wonder if you checked for an exhaust leak.

That's right and it was pretty mild with the 10w30 too! It's definitely internal because it is effected by what oil I put in and ambient and engine temperatures. Seems to be the colder and thicker the oil, the louder the knock. My guess is it's the last crank bearing that is struggling to receive oil down the very long crank shaft that these engines have.
 
Originally Posted By: 19jacobob93

Should be pretty common sense that a thicker oil takes longer to be pumped over a certain distance than a thin oil... But yeah going thicker proved it wasn't a clearance issue but an oil delivery/supply issue and I'm pointing my finger at the oil pump because they are what delivers/supplies the oil to the components.


But what you're apparently not grasping is bearings with proper clearances don't knock without oil(at least with a small amount of residual oil from last operation)... The thick oil is being bypassed back into pan and the delayed arrival of oil to worn bearings is causing knock... The true test would be to install oil pressure gauge to verify it's producing 60-70psi(or whatever your equivalent is) at start up, if so oil pump is doing it's job...
 
Originally Posted By: TFB1
Originally Posted By: 19jacobob93

Should be pretty common sense that a thicker oil takes longer to be pumped over a certain distance than a thin oil... But yeah going thicker proved it wasn't a clearance issue but an oil delivery/supply issue and I'm pointing my finger at the oil pump because they are what delivers/supplies the oil to the components.


But what you're apparently not grasping is bearings with proper clearances don't knock without oil(at least with a small amount of residual oil from last operation)... The thick oil is being bypassed back into pan and the delayed arrival of oil to worn bearings is causing knock... The true test would be to install oil pressure gauge to verify it's producing 60-70psi(or whatever your equivalent is) at start up, if so oil pump is doing it's job...

Sounds about right to me! I'm guessing the bearings will have some wear since most of the cars life before I got it, it was getting 20k+ oil changes as a rental car getting beaten on constantly I'm guessing. But even so it's strange that it would be having bottom end knocks and bearing wear at 220k when these bottom ends are famous for going 1.5 million KM (1mil miles) and more withouth work as well as the rest of the engine.
I also thought that if it was excessive bearing clearance I would have noticed in summer with the a/c running when the temp outside is 110F, which turns a 30 weight to water and is normally when a bottom end knock would happen. But my sotuation is different and puzzling but what you said sounds about right, especially with the thicker oil causing more to be bypassed back into the sump. I will try organise a pressure test and get back
 
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