Engine knock on semi cold start?

Cubey

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It got down around 28-30 early this morning, so I plugged in my block heater for about 2 hours. It is still working, since it made my radiator start to drip like it does when the engine is warm, and it started smoothly like it was warmed up, but there was a pronounced knock for a couple seconds:

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(I try to remember to turn on my dash cam first so it can catch things like this!)

It was impossible to tell where it was coming from, ie injector or crankshaft/rod. It went away as you hear in the video and it didn't come back. I moved over to the dump station promptly and shut it off to drain and rinse my tanks (took at least 15 mins due to the rinsing). When I started it again, no knock that time. A sort of normal thing sometimes, or...? Maybe the fuel filter got a bit gelled or something?

I drove 25 miles on the highway after the second start up and I didn't hear any knocking. I finally remembered to check the oil when warm (though it was an hour after shut off) and the oil is slightly overfilled from the oil change I gave it about 3 weeks ago, but only about 1/8" past the full line (at the vertical line in the "F" in "Full"). I've cold started and driven it a dozen or so times since the oil change (several times after 30-50 min highway drives) and that's the first time I've heard it. It was parked for 3 days so it may have just been an injector knock from the cold fuel, though it started perfectly on the first try and didn't sputter or seem like it was missing but maybe it still fired on the cylinder ok despite the injector complaining.

Or maybe a lifter/rocker due to cold oil?

The knock lasts 2 seconds or less and only on the first cold start, so I'm not TOO concerned since it went away once the oil started flowing, but I still wanted to ask. I will see about draining a tiny bit of the oil so it's not overfilled, in case that's somehow the problem.

I suppose it could even be a bad glow plug, and one cylinder isn't firing properly for the first couple of seconds? It has been starting fine without the block heater, but since I had free electric, I plugged it in to help avoid strain on the starter and batteries after the cold morning, because why not? For what it's worth, the cold timing advance is functioning properly.

And come to think of it, I have heard an odd noise before recently when cold starting (but less cold than lately), but it wasn't a loud knock like that. It sounded sort of "hollow" before but less loud. An old thread I saw on OB said that could be an injector/cyl not firing. https://www.oilburners.net/threads/hollow-thump-on-cold-start.54568/

Well, I guess I won't worry about it unless it gets worse since it's starting and driving fine.
 
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IDIBRONCO

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It's hard for me to guess due to it only lasting a couple of seconds. I thought it sounded like a lifter not being pumped up fully. An exhaust lifter to be more specific. If it happens more often, maybe you should try running something in your oil to clean out the inside of the engine for a short time before you do your next oil change. If it is a lifter, maybe that will help.
 

Cubey

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It's hard for me to guess due to it only lasting a couple of seconds. I thought it sounded like a lifter not being pumped up fully. An exhaust lifter to be more specific. If it happens more often, maybe you should try running something in your oil to clean out the inside of the engine for a short time before you do your next oil change. If it is a lifter, maybe that will help.

What would I run in the oil, diesel? I've read that it's ok if you just idle it for 5-10 mins before an oil change. (drain a quart or so then top off with diesel?)

What about something like this, no need to worry about removing it and it claims to help MPG and clean: https://www.hotshotsecret.com/stiction-eliminator/

It's rather expensive though, $50 for 64oz, and it calls for 4oz per 1qt of oil, so 44oz for an IDI with a PSD filter. That comes out to about $34 of the additive.

It's not hard to pull the drain plug to just remove a couple of quarts of oil, if I were to add in some of that sooner. Wish I knew if it would actually help my MPG, since I'm gonna be heading to AZ soon (850+ miles) and it would be nice if it helps the MPG to offset the cost of it. Diesel is about $4/gal out around Yuma too, give or take. I need every fraction of an MPG I can get.
 

sjwelds

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My truck sounds just like that sometimes. Always goes away in a few seconds after starting. Always only happens when ambient temperature is cold. I haven't lost any sleep over it.
 

IDIBRONCO

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I was thinking of running something like Marvel Mystery Oil or Auto RX. I suggested running it for a short time before draining the oil because I was suggesting using it to clean out deposits, sludge, etc. Assuming that it hasn't been done since 1985, there will be a large amount of crud inside your engine. This will come loose and you don't want it staying around your engine longer than it has to be there. It can also plug up your oil filter. It shouldn't cause an oil loss since we have bypass valves built in. It would cause a loss of filtered oil though. I was thinking of maybe 100 miles or so, then changing your oil to get rid of the freshly loosened crud, and then it won't hurt a thing to keep running the additive since the majority of the crud will be gone. Just in case, a shorter oil change interval when running the additive full time may be a good idea just in case. Maybe 1000 miles instead of 3000 (or however often you change your oil). Like sjwelds said, I wouldn't worry much about it unless it happens more often or starts lasting longer.
 

Cubey

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Well, I did some online shopping around and found that Napa has a $20 off promo code (including in store pickup) so I ordered a 64oz bottle of Stiction Eliminator for just under $40 with tax to try. I won't know if it helps MPG or not unless I try it. I can't find much mention of it being used in IDIs to know if it does much or not. Just lots of mentions here on OB about how "you should try it" for noisy lifters. I guess the high cost is off-putting.

My only concern is if it cleans things up TOO WELL and it starts leaking oil (worse than it already is, a fairly minor leak, from turbo maybe?). Someone with some newer diesel pickup said they put it in at 50k miles and it made their rear main seal leak, but it was under warranty so the dealer had to fix it. I don't have that luxury.

I mean, I can always cancel the order next week if I change my mind. I figured I'd at least get the order put in for now since it looks like it might be a "ship to store" situation since it estimates pickup for Wednesday. I'll be leaving this town on Thursday, so it has time to get to the store, if it even shows up. Napa's site has been bugged for YEARS, at least for me, not actually putting orders through from online. I guess we'll see if ths one works since I paid online, instead of choosing "pay in store" which I have tried to do in the past with the orders never existing outside of Napa's website, even when I take the order # into a store and provide it.

I'm in a place where I can throw down a tarp and drain a couple of quarts of oil to add it in. It's only been about 250 miles since the oil change, so it's still plenty early enough to put it in, even factoring in my 2,500-3000mi OCI (heavy load + dusty conditions). I'm about to drive a long distance in a short amount of time, about 200 miles per day for 4 days to get out to Yuma, so it's a great time to run that stuff through.


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(The above section was typed right before the quoted post below showed up, but I hadn't posted it yet. Figured I'd leave it instead of starting all over)

I was thinking of running something like Marvel Mystery Oil or Auto RX. I suggested running it for a short time before draining the oil because I was suggesting using it to clean out deposits, sludge, etc. Assuming that it hasn't been done since 1985, there will be a large amount of crud inside your engine. This will come loose and you don't want it staying around your engine longer than it has to be there. It can also plug up your oil filter. It shouldn't cause an oil loss since we have bypass valves built in. It would cause a loss of filtered oil though. I was thinking of maybe 100 miles or so, then changing your oil to get rid of the freshly loosened crud, and then it won't hurt a thing to keep running the additive since the majority of the crud will be gone. Just in case, a shorter oil change interval when running the additive full time may be a good idea just in case. Maybe 1000 miles instead of 3000 (or however often you change your oil). Like sjwelds said, I wouldn't worry much about it unless it happens more often or starts lasting longer.

Hmm, I see. Well, maybe I should forget the stiction eliminator right now then? I could always just get a spare oil filter and swap it out mid OCI, if it can it be pulled without making a huge mess, without draining the oil pan? Or keep it and put it in after the next oil change since it was a good price, even though I'm pretty tight on money this month and next.
 

Cubey

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Napa has their budget "ProSelect" filters for $5.29, so it might be a good choice for a very short run time? Here's the FL1995 equiv: https://www.napaonline.com/en/p/SFI21734?impressionRank=2

The filter on it now is a Shell Rotella filter (FL1995 equiv too) that I bought years ago from Walmart on clearance for $3 or $4 so it's probably similar in quality to the ProSelect filters, if not the same exact thing with a different label.

Maybe I should just go ahead and drain ~2qts of oil (since it's a tad overfull right now anyway), add in the 44oz of SE, and oil top off if needed then make the ~850 mile drive. After I get out there, just remove and replace the oil filter, so I only lose ~2qts of oil again. Then put in 6-8oz more SE and the rest fresh oil directly into the new filter, and oil topped if needed, and run that until it's due for it's next full oil change (80,956, going by 2,500mi OCI) which would be about 1,200 more miles. That beats throwing out an entire engine's worth of oil with only 250 miles on it right now since I'm kind of determinate to do this now. I need this engine to last as long as it can, so ~$50 to do this isn't THAT bad. I can borrow that from savings and replace it in a few months.

That would give it a good long run time over just 4-5 days (not something I do very often) with something that says you can leave it in, giving it a good chance to do a clean-up on a cheap filter with still pretty fresh oil, then replace it with another cheap filter in case the current filter gets sludgy, and let it do more cleaning up on the second filter during the shorter once or twice monthly drives I'll be doing from then on for the most part, until the next oil change comes due.

There's the slight chance it might help my MPG too which would be great too. It would help pay for the SE, if it actually does help on this vehicle. I'll be going 55mph as much as I can to squeeze out every MPG it can give. Just a 0.3mpg gain can save $20+ on a 850 mile drive when we're talking 8-9mpg.

I should probably put in some synthetic gear oil too before next summer too to help the MPG perhaps, since it should be pretty cleaned up by now. I put in cheap dino 80w90 oil since it was so nasty looking when I got it in 2019. I drained it again in 2020 and refilled it with dino 85w145. It's an open diff, so no friction modifiers are needed. That reusable diff gasket has been well worth the extra cost.
 
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IDIBRONCO

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Just so you know, it is possible to change the filter without draining the pan or making a big mess. Here's what I do. First, just turn the filter enough so that you don't need a wrench to loosen it, but not enough for the oil to leak out of the top gasket. Next, use a screwdriver (I use a #2 Phillips) and poke a hole in the lowest part of the bottom of the filter. You'll probably need a hammer or similar tool to make the hole. Let the oil drain out of the filter. Lastly, you can spin the filter loose by hand. I like to keep my index finger over the hole to lessen the mess (there will probably be an almost invisible oil stream still coming out of the hole which it why I loosen the filter before putting the hole in the bottom). You will hardly make a mess at all by doing this unless the wind blows the oil over the top of the drain pan. I know that you wear gloves while working on your RV like I do so you won't even get your finger oily when doing this.
 

Cubey

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Just so you know, it is possible to change the filter without draining the pan or making a big mess. Here's what I do. First, just turn the filter enough so that you don't need a wrench to loosen it, but not enough for the oil to leak out of the top gasket. Next, use a screwdriver (I use a #2 Phillips) and poke a hole in the lowest part of the bottom of the filter. You'll probably need a hammer or similar tool to make the hole. Let the oil drain out of the filter. Lastly, you can spin the filter loose by hand. I like to keep my index finger over the hole to lessen the mess (there will probably be an almost invisible oil stream still coming out of the hole which it why I loosen the filter before putting the hole in the bottom). You will hardly make a mess at all by doing this unless the wind blows the oil over the top of the drain pan. I know that you wear gloves while working on your RV like I do so you won't even get your finger oily when doing this.

I usually don't make (much of) a mess when I change the oil. I throw down a cheap blue tarp to catch any drips/spills, and the 12.5qt oil pan I use has a huge funnel so it can't tip/spill like an open pan. It's pretty forgiving about drips coming from the top of an oil filter too if I have it under the filter, due to the funnel size. As long as I don't drop the filter, it's not too messy. LOL It fits under the oil pan with room to reach in for the drain plug when I do drain it, so it's a great pan for DIY on-the-road IDI oil changes.

I try to remember to wear gloves but sometimes forget. I think I did remember this last time I did an oil change. I have a cheap rubberized pair that work well for that and oil level checks. I use them for dump stations and diesel fueling up too in fact. They sit on the floor under the driver's seat, door side.

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IDIBRONCO

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That's a couple more advantages to draining the filter like I do. The filters weigh less and they aren't slippery on the outside from oil running down the side. I have dropped full oil filters and they do make a huge mess when that happens.
 

Cubey

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That's a couple more advantages to draining the filter like I do. The filters weigh less and they aren't slippery on the outside from oil running down the side. I have dropped full oil filters and they do make a huge mess when that happens.

Oh most definitely. I'll keep that in mind for sure. I have a 4lb sledgehammer (it's been mighty useful!) so I have a way to get at it with a cheap stubby screwdriver or something like that.

And this is all assuming Napa's site isn't still completely useless and broken for online orders. Unless I have the bottle of SE in my hand, I'm not gonna do anything. If they still haven't gotten their crap together and fixed the site, I'll just forget the whole thing for now.
 

Cubey

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Eh, I just decided not to bother and did a refund on the stuff. It didn't knock any the other day when I started it for the first time in 5 days, but it also wasn't that cold. Stiction seems to be more of a thing with injectors that have oil passing through them. so I doubt the $40 is worth blowing on additive in an IDI.

It's gonna be down to 23*F overnight tonight but I'm on grid still, for the last night before I head to the LTVA. I'm gonna plug in the block heater this evening so it has plenty of time to get and say warm, since I would like to hit the road by 10am if possible, or at least get to the gas station to fuel up by then. I want to make a 200 mile drive at minimum tomorrow, if not 250. That's 4-5+ hours at 55-60mph, with slow downs oh some steep hills, and passing through towns/cities on the highways between here and Las Cruces, plus breaks, eating, refueling, and stopping before dark. I avoid driving at night at all costs due to poor eyesight. The seats in this thing aren't the best, so that's probably partly why it's tiring to drive more than an hour to an hour and a half at a time.
 
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