camotruck55

I have a 2000 Silverado Z71 with a 5.3 Vortec, 140,000 miles. I'll start back about a year and a half ago. For a few years I was taking it in for cheap oil changes. At one point I started having a lifter tick. It would tick for the first min or so. I decided to start doing my own oil changes, the tick was mostly gone for the first 2000 miles of the oil changes, then it would come back around. I used Pennzoil (I think) oil treatment on 2 of the changes. Seemed to help the tick.

Also at some point while getting those cheap $20 oil changes, a cheap filter came apart. lots of crap and fiberglass screenings in the oil. Anyway, I am noticing alot of sludge in the oil changes. I think the sludge may be building up on the bottom of the oil pan also. I also noticed a small amount of foam in the oil drain pan on the last change. I am losing a small amount of coolant in the reservoir without any visual leaks.

I am assuming a leaky head or intake gasket? Will any of those coolant sealers (K-seal?) help me with a temp fix? I'm getting different ideas from different people to take care of this. My current situation is to keep an eye on the coolant level and do frequent oil changes. I am even thinking of changing out the filter when I get to 1000 miles on this change. The last filter was very heavy even when the oil was drained out of it,I think it was full of sludge.

I am babying the motor and only driving it back and forth to work. I would like to milk this thing out until I am in a better situation to get it fixed. Any ideas?

f5fstop

You can start out by removing the radiator cap and letting engine warm up and see if you get some bubbles in the radiator; that is a sign of a leakage inside the engine or cylinder head (or gasket).
You can have an air leak down test performed that will help pinpoint where the problem is.
But if you have as much sludge as you are implying with the filter, it is probably too late.
Coolant in oil makes sludge. Sludge does not go through the engine channels effectively; thus, your engine is not getting lubricated as it should. After a while, this relates to a complete engine rebuild since the bearing will be destroyed from lack of lubrication and cooling. Oil is not only used as a lubrication it is an effective cooling agent too.

camotruck55

Thanks for the info. I reconnected with an old friend that is a mechanic. He is willing to do the work as a side job. He says we can put a pressure test on the coolant system and maybe find more answers there, but like you said with the sludge, its already there. Thinking about going ahead and getting it fixed now before more damage.

MDTAHOE

The intake manifold is dry on a 5.3L engine. There is no coolant in it. If you have coolant in the oil it can only from the heads or head gaskets. There is a TSB for a porous leak in the heads for certain years and engine. The TSB was titled "Coolant loss with no visible leak". Post the 8th and 10th digit of you vin# and I can tell you if it apples. Then you will have to remove the valve covers to check for brand of the heads in the casting.

camotruck55

8th is T, 10th is Y.

Thanks.

tblentrprz

I realize this is an old thread but hope this helps someone. The small head bolts under the edge of the intake, loose torque and allow coolant to seep into block from upper water port down the valve lifter opening. Torque the 10mm socket cap head bolts (M8) to 22 ft lbs starting at the center and alternating outward. You may be able to do this with intake on after you remove some plastic from the intake manifold gasket retainers. You’ll probably find the bolts by cylinders #2 and #7 the loosest. 99 - 01 use the old style non MLS head gasket, not sure if the 2002 and later MLS motors loose torque or not.

My experience:
2001 5.3 Suburban with 208K miles. It started losing coolant over the last 4000 miles with no apparent leak. Started up on a 50F degree morning and the engine sounded terrible. Ran great the day before approx 60 miles then parked. Only 750 miles on the Castrol GTX oil and AC Delco filter. I noticed oil pressure a little lower than normal and erratic, bouncing 25 - 40 psi. Pulled oil drain plug and out comes black sludgy blobs. Cut open filter and clogged with sludge in bottom 1/4. This engine does have the Castech 706 heads - known to crack per GM TSB 06-06-01-019B.

Diagnosing the problem:
Lower coolant level in engine block (loosen thermostat housing to drain R and L side). Pressurize the cooling system to 15psi. I could hear air in the crankcase. It was loudest around #2 cylinder, especially in the recess (under valve cover) of the front head bolt. Using water/liquid dish soap mix, I confirmed the head was not cracked in the recess. I removed the right cylinder head. While doing so, I realized that the small head bolt (under the edge of the intake) at #2 cylinder was loose and likely the root cause. With the head off, you'll see this head bolt holds the head down around the water port the feeds the head from the water pump. The head gasket looks intact. Since I only removed the right head, I prepped the head and block for head re-installation. Installed a new head gasket and head bolts. Torqued R head to spec. Re-torqued L head 8M bolts to spec. Retested for air leak - no leak, good to go! Fill crankcase with cheap oil and engine flush. install filter. Run per flush product recommendation then change. I'll do another flush after 500 miles. Should be good for another 100K!!!

Side Note - If you suspect a cracked head, you may need to run the engine to heat the head and then pressure test to expose the crack. If you run without coolant, remember to remove drive belt so you don't overheat the water pump seal. Careful to not overheat the head.

jeftahoe01

hi,


I am having, basically the same problem as Camotrucks55....... we did a pressure test 3 months ago --- to determine where the missing coolant was and could not find it. Over the last 3 months --- went thru 2 gallons of antifreeze ( 50/50 ) and at last oil change 2 days ago ---- Found the sludge


my 5.3 motor has 142,000 --- and my mechanic is recommending we drop a new motor in it --- $ 4000-5000. We like the truck and have had it for 12 years --- so may end up doing it since taking apart the engine and checking the heads --- and or replacing them will cost me $$$ , so maybe dropping a new engine in it is best .


MY QUESTION : I will ask my mechanic --- BUT where would YOU GUYS recommend we get the engine from ?


JASPER , CRATE ENGINE DEPOT , ETC ?


Since I have a 2001 Tahoe 5.3 --- I read someone else post in 2012 to get the NEW 1999 eng -- stock # 12457705 -- then re-use the top end & front end from the original motor ?


any help or thoughts would be helpful


Jeff

tblentrprz

Jeff,
What about a good used engine? The motor I got was like new and still had the hone marks in cylinder walls. FYI - 2005-2007 with rear cam sensor and 13mm valley pan or exhaust manifold bolts will be the gen IV engines with floating piston wrist pins and stronger connecting rods. Not that it makes a significant difference on a low hp daily driver.

How long was the engine run with low or no oil pressure? If oil pressure was above 15psi and only some lifter noise for 10 minutes at idle, no problem. If it was driven with lots of engine noise than the risk of internal damage is high. Roller lifter(s) will likely fail.

If you think the motor is still good besides the leak, why not make sure at least the RF and LR small head bolts are torqued to spec? (If loose, wouldn't hurt to verify all the small head bolts)

If I encountered the coolant loss problem again, I would torque above mentioned head bolts. Lower coolant level below heads and pressure test. Should hold pressure and no leak/hiss in crankcase should be heard (pull oil fill cap and put hose or stethoscope in to listen) If no leaks, suck out any sludge you can through oil drain plug hole. Run a can of motor flush with cheap oil and filter. Change oil and filter with quality products (eg. Castrol GTX). Likely good to go for 10s of thousands of miles.

If you still have a leak and head castings are 706, you'll need to pull rocker covers to check for cracked casting/leak (pressurize cooling system and spray soapy water in head bolt pockets). As you said, may be cheaper to get a replacement engine if the rest of the truck is worth the cost.

I use factory remans (check with your local dealer - nationwide part and labor warranty - 3yr/unlimited mileage) or rockauto.com (approx $2050 shipped. Check on warranty, I believe it is 3yr/100K miles and shipping covers core return)

Hope this helps.

jeftahoe01

hi, I appreciate your response , and yes a used engine can be bought at junkyard for $ 800-1100 based no year and miles , etc ...... literally just got off the phone with my mechanic , going over the options, etc . when we did the pressure test -- nothing was coming out anywhere. Oil pressure has always been GREAT , only have lifter noise at cold startup for 1 minute, then after that -- truck runs great and no noise. My Mechanic has quoted me numbers that I feel are a little high----- I had been doing my own research online in preparation for their phone call this morning. he wants $ 2700 for head gasket repair and machining of heads..... I don't know why he did not quote me --- order and install new heads and gaskets.... he wants $ 3900 for installation of used motor with a warranty...... he wants $ 6300 for new jasper motor and installation ( strange when jasper motor costs $ 3200 basically ) ....... still trying to figure out what to do

tblentrprz

Good news - sounds like motor is usable and likely will live another 100K miles. I think prices are too high. Might need to find another recommendation on mechanic. Ask around, check yelp, etc. Used motor price higher than expected. Call dealer and rockauto about their motors and warranties. You could have one delivered to installer.

Don't pressure test with coolant since it's not an external leak. Pressure test with coolant drained below heads and listen for leak in crankcase. Re-torque RF and LR small head bolts takes 10 minutes at most. The leak should be gone unless you have a cracked head or engine was overheated (due to low coolant) and head/gasket failed.

Since I uncovered the problem on my own vehicle and could have eliminated replacing the motor, I check small head bolt torque for my customers on these LS engines and often find them to be 8-16ftlbs instead of 22 (spec).

What head casting? Look at RF corner just below edge of rocker cover. 862 good, 706 could be problem. If heads/gaskets are a problem, It may be more cost effective to consider engine replacement depending on miles/wear on existing engine.