losing coolant and lifters tapping

[Dpounders]

I recently purchased a 2005 GMC Yukon 5.3L with 172K. I noticed that the heat wasn't working but I found the coolant low, topped it off and it worked fine. However, it seems to be consistently losing coolant at a rate of about a 1/2 gallon per 800 miles. I changed the oil as soon as I purchased it a couple of weeks ago using NAPA 5W-30 and a NAPA Gold filter. This past weekend I went camping with our boy scout troop and towed their trailer about 300 miles mostly on the interstate. After getting home, the next morning I started it and there was what sounded like a lifter tapping for about 30 seconds and then started quieting down and was completely gone after about 45 seconds. The vehicle runs perfect and no sounds after that. If I shut the vehicle off and restart the tapping is not there. It's only when it sits for about 8 hours that it starts to tap again on cold starts. Weather is about 30-45 degrees in the mornings. Any ideas?

 

[ATL]

these motors are known for making tapping noise on cold startup, thats perfectly normal. but keep an eye on the coolant. try your best to find a wet spot on or around the motor. lets hope its leaking externally and its not a head gasket

 

[Dpounders]

I can't find any signs of leaking externally on the ground or the motor. However, I checked the oil and I don't see any sign of coolant there either (no cloudiness, bubbles, film, etc.).

 

[ATL]

when i had a head gasket go bad, the coolant didnt make it in the oil, but it made it in the cylinder everytime i turned it off. it would idle rough for 5-10 seconds on crank up and be fine. but take a look at the underside of your water pump

 

[Dpounders]

Yeah it definitely doesn't run rough on start up at just has the ticking/tapping sound for 45 seconds. Have you or anyone ever tried adding Lucas Heavy Duty Oil Stabilizer or anything similar to the oil to try to eliminate the ticking/tapping sound? Is it possible that the coolant could be causing this sound on startup somehow?

 

[ATL]

most of the time that sound is piston slap. its caused by the tolerance differences in the pistons and block. once they heat up alittle and swell, the sound goes away. you may have the aluminum block 5.3, its highly sought after motor but unfortunately the aluminum blocks have more piston slap than the iron blocks

 

[Dpounders]

If it was piston slap wouldn't the sound start appearing gradually and get louder. This motor was quiet and then all of a sudden started doing it.

 

[chauncey0337]

"Piston slap" happens mostly when the temp is cold. And like ATL said it's common on these trucks. I've heard replacing the oil pick up tube o ring can fix the slap. Whether it works or not, I don't know for sure. Also heard the 2 cycle oil treatment helps.

 

[M3PO]

Agreed, tapping sound is common.
The coolant consumption is something to check out, as mentioned before you could have a head gasket or other issues.

 

[ATL]

i dont believe there is a fix for the slap, its the tolerances. aluminum contracts and expands more than iron, thats why the aluminum blocks slap worse. as the aluminum is heated, it expands, tightening up the tolerances between piston and cylinder causing the slap to go away.

if the sound just started, i wouldnt assume it to be piston slap. but im wondering with it being a new vehicle, maybe its just something you never actually listened for. but after that oil change, the mechanic in you made you stop what your doing and listen to make sure everything was done correctly.

 

[01HDtahoeNJN]

My pistons slap when it sits and it's cold out as well.... And my coolant is vanishing (no bueno)

 

[TnTahoe]

I lose a lil coolant here and there but not 1/2 over 800 miles, i've read something about having cracked heads will eat some of your coolant

 

[lawjack]

My denali had the same problem with losing coolant every now and then. I found the leak where my hoses connected to my radiator, apparently the sides of the radiator are known for letting little cracks form. When i revved the engine you could see a small stream of water shoot from the radiator.. alittle jb weld fixed mine.

 

[gnilson]

I had the same thing happen to me. I had owned the truck for about a month, no tapping coming from the engine. Then one cold morning, I started it, got out and headed back inside. Just as I got to the door, it started making the ominous tapping sound. Over the past 3k miles, it has gotten progressively worse. Fortunately I purchased a 2 year warranty with it and plan on using it.

For the coolant leak, I would have the system pressure tested. That should bring to light any pin-hole leaks.

Good luck.

 

[yukonic]

i have an 01 5.3 that started making the tapping sounds this winter. just like others stated, it happens on cold starts in the morning but once i drive 1/2 a block it goes away...

 

[Redhoe01]

I recently purchased a 2005 GMC Yukon 5.3L with 172K. I noticed that the heat wasn't working but I found the coolant low, topped it off and it worked fine. However, it seems to be consistently losing coolant at a rate of about a 1/2 gallon per 800 miles. I changed the oil as soon as I purchased it a couple of weeks ago using NAPA 5W-30 and a NAPA Gold filter. This past weekend I went camping with our boy scout troop and towed their trailer about 300 miles mostly on the interstate. After getting home, the next morning I started it and there was what sounded like a lifter tapping for about 30 seconds and then started quieting down and was completely gone after about 45 seconds. The vehicle runs perfect and no sounds after that. If I shut the vehicle off and restart the tapping is not there. It's only when it sits for about 8 hours that it starts to tap again on cold starts. Weather is about 30-45 degrees in the mornings. Any ideas?

I posted a while ago that I had piston slap after switching to Mobile 1 and then developed a tick from a lifter. I took my truck to a family friend thinking my heads were junk. He is a long time Chevy mechanic that worked for GM and then opened his own shop after retiring. Without telling him he asked "did you switch to synthetic oil" and I said yes about a month ago. He said dump that shit and put in some normal 5W30 and half a quart of transmission fluid in your oil. Trusting him like I always do, I put half a quart of trans fluid in my oil and within a week my piston slap was gone and the tick was one in two days. I stopped back in to tell him how successful it was and he told me that trans fluid has higher levels of detergent in them and cleaned the pistons and valve from any carbon pieces that came loose with the new oil. Never had a problem after that on a 5.3 with 155,000 miles on it. Just sharing my experience.

 

[chauncey0337]

I posted a while ago that I had piston slap after switching to Mobile 1 and then developed a tick from a lifter. I took my truck to a family friend thinking my heads were junk. He is a long time Chevy mechanic that worked for GM and then opened his own shop after retiring. Without telling him he asked "did you switch to synthetic oil" and I said yes about a month ago. He said dump that shit and put in some normal 5W30 and half a quart of transmission fluid in your oil. Trusting him like I always do, I put half a quart of trans fluid in my oil and within a week my piston slap was gone and the tick was one in two days. I stopped back in to tell him how successful it was and he told me that trans fluid has higher levels of detergent in them and cleaned the pistons and valve from any carbon pieces that came loose with the new oil. Never had a problem after that on a 5.3 with 155,000 miles on it. Just sharing my experience.

Thanks for sharing! Very interesting.

 

[trik]

Yeah it definitely doesn't run rough on start up at just has the ticking/tapping sound for 45 seconds. Have you or anyone ever tried adding Lucas Heavy Duty Oil Stabilizer or anything similar to the oil to try to eliminate the ticking/tapping sound? Is it possible that the coolant could be causing this sound on startup somehow?

I have a 01' Denali 6.0...

Every morning, when I start her up she too plays the taps...I got her in 04' with 40k and as the years went by, she now has a 126k, the tap got louder... Just by listening, I traced it to the front of the driver side...

( Coolant has a way of disappearing on mine too, I just keep filling her, I all ready know it's my water pump... check the water pump first from the bottom of the car, also the sides of the radiator ;like the dude said earlier, if coolant is passing thru a head gasket you'll see and smell it in the exhaust... also on the rough Idle, theres a bad flaw in the oil separation design, on the 6.0 it gets routed right behind the throttle body and leaves a thick residue film all over the interior walls of the manifold, I shot two cans of brake cleaner and throttle body cleaner right up the body while I was parked on a a incline, let me tell you what... it ran back out like the blackest of black you've ever seen, now, no more rough idle... remove the air flow housing to the throttle body and lift the butterfly, look behind it and/or stick a finger behind it a wipe it around in there if it comes out anything but clean shoot some cleaner up there and stick a rag as far in as you can get to wipe it clean as best you can.. )

I consulted a few mechanics and most agreed that it is a lifter that sticks a bit until the oil pressure builds enough to lube it properly...

Hence why it goes away quite rapidly and why it only happens after sitting for long periods of time...

I tried the lucas after I made a huge mistake, at work and decided to do a quick oil change, had my Mobil1 filter and Synth Oil, Drained it, removed old filter and installed new one... The Bad - I didnt notice that the old seal did not come off with the filter ...

So i'm all done, go to start and within 5 seconds all my fresh Mobil1 was on the floor and no longer occupying the space where it belonged ...

So hear I am miles away from any auto parts store, so what do i do? ...

I Drive concrete trucks, so I go over to the shop, siffon off 5 quarts of heavy weight truck, oil filler up and go on my way with the intention of just making it home 12 miles away and changing out for the right stuff the next day...

Low and behold I wound up driving it with the heavy oil for five days... now it the morning the tapping is still there and a bit more prominent but still goes away with in 45 seconds...

I added Marvel Mystery oil and Lucas and both helped a great deal..

Even though its most common knowledge that when you get an oil change rule of thumb is five quarts... not so in my case.. the 6.0 needs 6 quarts..

This is why this sound occurs in most engines... ( in my opinion )

I don't care what mechanic, dealer, book tells you to do.. add a half to a full quart extra dependent on what size engine you have... ( once more, just my opinion )

The book the Denali came with actually says fill with 6 quarts...

After years of just using quick lube joints that don't know any better and fill with five quarts instead of six hear we are...

Try the Mystery Oil first... or the Tranny fluid sounds like a great idea... i'm going to do that tomorrow ... and I think I'll go back to the real oil too, you cant believe a word " THEY " say, for all we know synth oil could very well be crap.. Trust no one...

Sorry if i went over-board with my reply.. it's late, I'm Drunk ... Good luck.

 

[Kman]

I posted a while ago that I had piston slap after switching to Mobile 1 and then developed a tick from a lifter. I took my truck to a family friend thinking my heads were junk. He is a long time Chevy mechanic that worked for GM and then opened his own shop after retiring. Without telling him he asked "did you switch to synthetic oil" and I said yes about a month ago. He said dump that shit and put in some normal 5W30 and half a quart of transmission fluid in your oil. Trusting him like I always do, I put half a quart of trans fluid in my oil and within a week my piston slap was gone and the tick was one in two days. I stopped back in to tell him how successful it was and he told me that trans fluid has higher levels of detergent in them and cleaned the pistons and valve from any carbon pieces that came loose with the new oil. Never had a problem after that on a 5.3 with 155,000 miles on it. Just sharing my experience.

Great story. The ATF trick is an old one but does work. I might put some in before my next oil change to loosen up the carbon build-up.