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#3563 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [rfletcher]
Oct 04, 2010 (11:29 am)
The one-piece rear crankshaft seal can be replaced with the engine in the car. The oil pan must be unbolted from the block and dropped down one or two inches, the starter, transmission, torque converter, and the flex plate (flywheel) must be removed so you can un-bolt the old seal and housing from the block so you can pull it off the cranksahft. . A new main seal and housing assembly is installed in the reverse order. The new seal and housing kit can be purchased from any GM dealership parts department. The most difficult part of the job was previously installing a new seal in the old seal housing. GM eliminated that problem for us. The new seal and housing kit has the rear seal already installed in the housing and the whole assembly is ready to be installed on the crankshaft and bolted to the block. A new gasket must be installed between the seal housing and the block and the gasket probably comes in the kit. If it doesn't come in the seal kit, the housing to block gakset can be purchased separately for a dollar or two. It should take an HONEST auto repair shop about 8 hours to do that job as described, at a cost of about $500.
The seal kit is GM part number 14088556 with a MSRP of $66.43. The kit is STILL AVAILABLE as of this date. It is a one piece seal and housing with the pan studs already installed in the seal housing. The engine does not have to be removed to install the one piece seal kit like the 2 -piece seals found on the 1986 and earlier V6 and V8 Chevrolet engines. The front of the block does not have a seal like the rear crank seal so it is probably the front timing cover gasket or timing cover crankshaft seal that is leaking. The radiator, serpentine belt and front balancer/pulley assembly must be removed and the crank seal must be replaced. It is located in the metal timing chain cover. If you are in the used car business, this not cost effective since the resale value of the car is about $2000. It is a good investment if you plan on keeping the car for another five or six years.
Since the one piece rear cranshaft seal is still available at any GM dealership (special order) I will buy a couple of spares for my '91 S10 Blazer 4x4. That is because every time I start liking a product, it is not around very long. If it is discontinued, it will not be long before an aftermarket company starts making it. However, I try not to buy anything but AC Delco or Genuine GM parts, even if they are made in Mexico and China. Unlike American manufacturers, the Chinese have excellent quality control......they chop your head off if you make a mistake.
I have rebuilt a .030" OS 4.3L V6 engine for my 1991 S10 Blazer 4x4 with forged 350 V8 pistons and a high-performance comoputer compatible camshaft. I am the original owner and the vehicle is in showroom condition with only 150,000 miles on the odometer. . I am continually replacing parts on that vechicle not because they have failed, but just because they are 19 years old . I am not in the used car business so I do not worry about making a profit if I someday sell the vehicle. I sold my '63 Pontiac Catalina 421 HO for $16,000 and I had $50,000 invested in it. That is what happens when two fools meet.
#3564 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [duntov]
Oct 04, 2010 (12:17 pm)
Thanks duntov. Great answer and I certainly appreciate it.
I had no thoughts about doing this one myself. Wanted to be somewhat educated before approaching a shop. I can't say mine is anywhere near showroom appearance but not bad and has served me well. I am surprised at your estimate. Being so labor intensive, I feared much more. The ball joints and axles cost $663. The operative word is HONEST.
The other question is "pay me now or pay me later". I have no way of knowing the condition of the rest of the engine. Since you guys helped me back in July, the truck is running very well. Gas consumption about as always before. Not good but no different. Oil pressure 40 +/- 5. No evidence of burning oil. Never had to add before this leak. Always changed oil and filter religiously. It still has the power to, easily, pull my 26 foot boat up a steep ramp. Low range 4X4 of course.
#3565 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [rfletcher]
Oct 04, 2010 (6:42 pm)
If the oil pressure is good, and the engine uses no oil between changes, the internal condition is probably good. Your frequent oil and filter changes are the key to this.
My 98 Blazer has 210,000 on 4.3 V6. I haven't needed to replace the rear seal yet.
I did replace the timing chain and cover. Rockauto had the cover complete with gaskets for $20, and the gasket set alone was $12. Since the truck is 4WD, another source of leaks was the hose assembly for the remote oil filter, so I had it replaced also.
For any part that is labor intensive, buy the best parts you can get. Don't want to do the labor twice because of cheap parts.
Good luck with the Blazer.
#3566 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [johnss10]
Oct 05, 2010 (3:56 am)
It's going into the shop this week. Think I will keep this one for as long as I can, Better the devil you know. In hindsight, I may have caused this problem myself. Lot of guys recommended SeaFoam for older engines. I used it in the last oil change. Now this problem. May have killed it with kindness as I sometimes do in my garden with too much fertilizer. A case of, " if it ain't broke, don't try to fix it."
Thanks for your comments.
Oct 05, 2010 (7:38 am)
I have never used Sea Foam and probably never will. When my 1991 S10 Blazer got 120,000 miles on it, I switched to Valvoline Max-Life motor oil and I have used Chevron gasoline with Techron and now my Blazer has 150,000 miles with no leaks and it runs smooth as silk. I first thought Techron additive was just a gymick but if you use Texaco or Chevron gasoline with Techron blended at the refinery, it definetly keep the fuel injectors clean and reconditions the fuel pump. . Techron was specifically introduced for fuel injected engines and will do very little for carburated engines.
At 120,000 miles, I also replaced my o2 sensor and the EGR valve and it nearly felt like a new engine in about 100 miles when the computer reprogrammed itself to the new parts. The OE EGR valve was completely coked up with carbon deposits. I cleaned out the intake manfold EGR ports before I installled the new EGR valve. The old cliche "If it ain't broke don't fix it" does not allways apply to some parts on automobiles. For automobiles it should be: "If it ain't broke, fix it before it is broke" That is called "maintenance". Many parts on tmodern cars nowdays are "wear parts" and should be replaced according to the mortality of the part or before they fail completely. Shock absorbers, ignition coils, ignition wire, ignition module, EGR vavle, spark plugs, distributor caps, rotors, ect. are just some of the thing that need routine replacemnt. Of course, you must take the over-all condition of the vehicle into consideration and what you want to do with it. I have a fresh engine ready to install in my 1991 S10 Blazer that cost about $3000 to build. If I wanted to sell my 1991 S10 Blazer the day after I installed the engine, I could not ask more than $3000 for it.
I recently junked my 1998 Ford Crown Victoria with 90,000 miles that had a broken timing chain. The timing chain broke and bent some valves. I figured up the cost to fix the engine and it would cost more than the car is worth. I should have spent $500 and replaced the timing chain at 60,000 miles just as Ford recommended, before it broke and ruined the engine. .
#3568 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [rfletcher]
Oct 05, 2010 (9:11 am)
I have used the SeaFoam in my 1996 Blazer... 210800 miles... in the gas only. Most likely what happened to cause your seals to leak... same as when you start using synthetic oils on higher mileage vehicles... I use Amsoil only... is the false seal created by crude was dissolved away... allowing for a temporary gap in the seal and the surface that it was sealing... this will most likely seal itself... as the seal will return to its original position before the crude build up. I have experienced this when converting high mileage vehicles... over 80K to synthetics (Amsoil). Hope this helps.
#3569 of 3676 Re: Oil leak, rear crank seal, 91 S10, 4.3 L, EFI [quantumtouchfl]
Oct 06, 2010 (4:51 pm)
UPDATE; Thanks to all for your help. Got the car back this PM. Was not the crank seals. Something they called Housing adapter. Maybe oil lines to the cooler. I don't really know. O ring kit$17.44, labor $118.50. What ever, --- I'm happy. I think someone suggested this as a possibility. As to the " if it ain't broke don't try to fix it", school of thought, I have to agree to a point. That being that, other than truly routine maintenance, most of us have no clue until it stops running. I envy those who are that knowledgeable and appreciate your help.
New subject; Why would it cost $500.00 +, to replace the motor mounts. One under the Trans., Two under the engine? Again, I have no clue.
#3570 of 3676 Oil leaks and Maintenance
Oct 06, 2010 (10:47 pm)
In concurrence with duntov's comments. I had the timing chain ( and cover) replaced before the thing broke and left me stranded beside the road. Same deal with remote oil filter hoses. If they fail while going down the road, all the oil gets pumped out of the engine before there is a chance to do anything about it, Fortunately, your leak was easy to fix. Sounds like it was the oil filter adapter.
No clue on the cost of the motor mounts, other than maybe it's mostly labor because GM's fine engineering made them so hard to get at.
Oct 07, 2010 (4:32 am)
The problem could have been any one of a number of oil system parts.
The one piece crankshaft seal housing adapter retains the rear crankshaft seal. The seal can be replaced without replacing the housing adapter but it is easier to replace the whole assembly as a unit. It was probably not that that failed because it would have cost more than what you paid to replace it. The one piece crankshaft seals rarely fail.
On a 4x4 Blazer , the oil leak you had was probably the remote oil filter / oil cooler hose adapter gaskets or the oil cooler / oil filter hose O-rings seals. That adapter bolts to the block with two bolts where the oil filter is located on 2WD Blazers. The oil cooler and oil filter hoses are attached to the adapter with one bolt with a gasket and have "O" ring seals that can fail. . The oil filter and oil cooler hose adapter itself cannot fail but the oil hose O-ring seals and adapter to block gaskets can. fail. The hose ends of the oil filter and oil cooler hoses are aluminim and can crack easily and leak. In that event the hose assemblies must be replaced with new O-ring seals. The oil filter and oil cooler hose assemblies are similar to A.C. hoses but are not high pressure hoses.
On a 4x4 Blazer, the oil filter and adapter is located on the left fender behind the radiator support. The oil filter adapter is connected to the oil filter and oil cooler hose adapter with two hoses paired together, one in and one out and come in two assemblies, the front assembly is from the oil filter to the oil cooler and the rear assembly is from the oil filter to the oil hose adapter that is attached to the engine block. The front and rear hose assemblies are pre-assembled with aluminum connectors and they are avaliable from Dorman for about $50. Those hose assemblies are also a wear item and should always be replaced when the engine is rebuilt or if they leak.
#3572 of 3676 Re: Housing [duntov]
Oct 07, 2010 (6:01 am)
Thanks to all for the new information. With so many potential oil leaks I think I see why GM used a pressure sensor that will also shut down the engine. This happened to me one night. I had recently replaced the sensor because the digital display was erratic. While driving the engine died. No loss of oil. Mechanical test gauge indicated normal pressure while cranking. Sensor was defective. Would not restart. I replaced the sensor next day, temp., with the old erratic unit. It started and ran normally. Installed a second new sensor. two days later failed again. I will never understand auto mechanics as you guys, obviously do. Wish they were as simple as a radar or a navigation system.
As to the motor mounts; your reason is close to what the shop told me. Almost all labor due to design.