Thread: the 5.7 and 4.3 Olds Diesel FAQ thread

The purpose of this thread is to provide a one-stop-shop for part numbers, recommended sources, and knowledge regarding the 5.7 Olds diesel and its cousins the 4.3L V6 and 4.3L V8 diesels.

Please keep posts on topic and helpful. Posts regarding your opinion on the engine aren't invited, warranted, or required. Every machine has weak points- and it's possible to engineer solutions for most of them.

I'm currently going through a couple of these engines and am posting this thread to share my knowledge. I am not the source here- -most of this has been gained from conversations at length with Dieselolds, LouPerfetto, and other folks. I'm hoping to save them some time and effort in the future-- they should be able to just point at the FAQ.

PARTS LISTING: prices from Advance Auto

-Harmonic Balancer bolt kit: ARP PN 180-2501: $32
-connecting rod bolt kit: ARP PN 184-6001: $106
-main bearing bolt kit: ARP PN 184-5002: $67
-head bolt kit (absolutely required!!): ARP 180-3601: $112
TOTAL: $317 +tax

Prices at Summit:
-Harmonic Balancer bolt kit: ARP PN 180-2501: $20
-connecting rod bolt kit: ARP PN 184-6001: $58
-main bearing bolt kit: ARP PN 184-5002: $49
-Head bolt kit: ARP PN 180-3601- $64
TOTAL: $191+ship

(various sources)
Olds Diesels come in a few varieties:

Oldsmobile produced diesel engines in 4.3L 263 CID V-6, 260 CID V-8 and 350 CID V-8 variety. The 263 V-6 diesel was available in Cutlass Cieras and Supremes from 1982 to 1985. It was also available in Ninety Eight Regencys in '85. All Diesels were discontinued for '86.

According to my sales handbooks and literature, the 4.3 V6 Diesel was optional on all Cutlass Supreme, Supreme Brougham and Calais models in '82, '83 and '84. This was in addition to the 5.7 V8 Diesel. Option code for the 4.3 was LT6 and retail price was $500 (opposed to $700 for the 5.7). The 4.3 was not available in RWD Cutlass Cruiser models.

The initial 260 and 350 diesels were very bad engines as they were delivered. Definitly, one of the major problems was an uneducated public and GM's unwillingness to do anything early on. Most people didn't have a clue about diesels and neither did the mechanics. Most likely that, coupled with bad fuel, and water in the fuel, and bad head bolts did them in. Engines of the first few years have everything from alternator mounts breaking, injector pumps blowing seals, to top end problems with head gaskets blowing, push rods bending, to rockers breaking. Generally the problems are with head gaskets blowing and injection pumps rusting.

Overall, the main ingredients of disaster that affected this engine lie in:

1) A poorly designed fuel system, which was fostered by a desire to insulate the consumer from the unpleasant aspects of Diesel ownership.

2) A misguided attempt to market the diesel engine as if it were as convenient to operate and maintain as a gasoline engine.

3) A poorly trained service staff which often used the incorrect oils and service procedures for this (and any, for that matter) Diesel engine. These factors combined to create the ultimate downfall of this engine. In the hands of an experienced diesel operator, these engines can (and often do) travel for hundreds of thousands of trouble free miles. However, for owners who would just "gas and go", this engine was particularly ill suited to the task. Not that it matters much now

4) Interestingly, Olds also made a Diesel V6 which WAS NOT plagued by the weak cylinder sealing problem. This engine was based on the V8 with two cylinders omitted. Since the V6 could not be machined on the same machining centers as the V8's, GM went ahead and added two head bolts per cylinder, for a total of 14 bolts per cylinder head (compared to only 10 for the V8) as the engineers had recommended on the V8 from the beginning. Had this recommendation been followed, the Olds Diesel V8 would have had 18 head bolts per cylinder head, which would have generated PLENTY of clamping force and the Oldmobile diesel V8 likely would have had a completely different service history.

According to a number of sources, the newer diesel engines were like night and day compared to the original ones. After Olds worked out the problems, many owners have 200,000 - 400,000 miles on them, and they are still going strong. The 260 diesel apparently holds up better than the 350 though.

1978 - 1985: Diesel production continued until 1985 when all diesels were discontinued for the 1986 model year. Diesel parts were being handled by Detroit-Diesel-Allison, and not Oldsmobile. Both AC-Delco and GM Goodwrench rebuilt 350 diesel engines are available. In terms of rebuilding, try a competent diesel truck mechanic. Olds diesels were also used in Chevy trucks.

1979 - 1980: The Olds 260 CID V-8 diesel, produced from 1979-1980, with a whopping 90hp and 170 ft/lbs of torque, it made the 2.5L "Iron Duke" motor look like a W-30 by comparison. I wonder why you never hear about buildups based on a "diesel-block 260"? Perhaps the only engine whose main journal bores were larger than the piston bores! (well, very nearly)

1982 - 1985: The 263 V-6 diesel was available in the Cutlass Ciera and Supreme from 1982 to 1985, 85 hp, 4.057" and 3.385" stroke. Basically a 350 with two cylinders chopped off. The V-6 Diesel was an option in the newly designed and FWD 1985 98.

-Use a high quality diesel-specific oil (Rotella?)

-install a hardened oil pump driveshaft, as the stock bit is known to round and strip out. Milodon part number 22575; $21 at Summit

-install a water seperator in the fuel line before the engine.

-install a fuel filter before the engine. (rating? 20micron ok?) Do this whether or not you use the factory "filter" at the back of the block.

-install ARP head bolts (head bolt kit (absolutely required!!): ARP 180-3601)

-use high quality head gaskets (Felpro KS2639 - 1979 OLDSMOBILE DELTA 88 V8 5.7 Liter Diesel w/ext EGR; INTAKE MANIFOLD GASKETS NOT INCL, use MS 9947-2; Premium valve stem seals incl.: $98 @ Advance. Or appropriate equivalent)

-use ARP main bearing bolts (main bearing bolt kit: ARP PN 184-5002)

suggested: ARP connecting rod bolts and HB bolt kit, as listed above

-Pencil injected heads were used from 78' to 81' in Chevy/GMC pickups

-External EGR engines used different intake manifold gaskets because internal and external EGR heads are different castings.The intake ports are of different sizes between these two types of EGR systems.

-If you have a single stud air cleaner you have external EGR.A 2 stud air cleaner would indicate internal EGR.

How do I attach the torque converter to the engine's flexplate?
Just bolt it up, assuming the engine was originally attached to an automatic (typically a TH350 comes on these engines).

The 700r4 TCC (torque converter clutch) is computer-controlled by the gas ECU. How do I get this working without a computer controlling the engine?

There's a couple ways: use a pressure switch on the 3rd gear pressure test port on the outside of the transmission, coupled with a relay off of the brakelight switch circuit.

Or use this relay kit from Bowtieoverdrives ******ADMIN NOTE: URL Removed******

For $70, you really can't beat the bowtieoverdrives kit.

How do I bolt the SBC-pattern 700R4 to the BOP pattern of the 5.7/4.3 blocks?

Couple ways:
Use the TCI SBC-BOP adapter from Summit, at ******ADMIN NOTE: URL Removed******

or, there's this fellow on Ebay that sells them for about half that price:
******ADMIN NOTE: URL Removed****** or search for Trifiver. MAKE SURE that you shim the flexplate to torque converter bolts by the thickness of the adapter plate. Otherwise the TqCon won't engage the pump on the transmission properly, and trans failure WILL result. Use a micrometer to measure the washers until you fine some that match.

How do I get the TV cable to attach to the throttle linkage?

Good question, and it MUST be done, or transmission damage will result. Apparently, the stock 5.7 linkage has a hole in the plate that works just fine for this purpose. Make sure you adjust the TV cable properly- there's tons of instructions on the web. http://www.purplesagetradingpost.com...o/700R4p1.html is a good place to start.

I don't intend to run AC, and I am running hydroboost for brakes, so I don't need this vac pump, right?

Well you might not need the vacuum, but if you take it out you're going to be removing the drive for the oil pump, and of course that's a bad thing.

Speaking of oil pump, the driveshaft is known to be a weak part. Better replace it with a Milodon part. (Part number to come from Dieselolds)

What's all this I hear about an oil pump driveshaft?
Courtesy of Dieselolds:
I've just installed the oil pump and milodon oil pump driveshaft into an olds diesel cylinder block I currently have on my engine stand.I inserted the vacuum pump but the pump did not bottom out as some people have stated with some brands of aftermarket oil pump driveshafts,but there is very little clearance in regard to the shaft sliding up and down in conjunction between the oil pump and vacuum pump.We're talking very tight clearances here.I measured the inside portion of the vacuum pump drive gear and came up with 1.323" and then i measured the depth of the shaft sticking upwards inside the engine block in regard to the mounting casting pad that the vacuum pump drive gear rests on.I came up with 1.202",but keep in mind I did not have the vacuum pump hold down clamp in place.

The body of the vacuum pump did rest flush on the engine block.It was not raised upwards at all.My opinion would be to remove just a very small fraction of material from the milodon shaft where it enters the oil pump.This in turn will lower the shaft further into the oil pump and that will ensure no binding of the oil pump gears in relation to the oil pump cover plate.The last thing we need is binding in that area.

So in turn the milodon shaft will work perfectly,but to be more comfortable I would recommend a minor modification be performed upon the shaft and then it would be safe to use.

The part number for the Milodon oil pump driveshaft is 22575.It's CNC machined and is of a 4130 chrome moly material.

Find the part at Summit: ******ADMIN NOTE: URL Removed****** Or search for Milodon 22575 in their search box.

This is the most frequently asked question I can think of.I've had excellent results with victor reinz head gaskets in regard to the olds diesel.The victor part number is 3736.The part number is for the .010 thicker than stock/.030 overbore design and is of a graphite material.

The .030 overbore feature is common on these head gaskets and can be used with a STD sized bore because this will enable the wire bead on the head gasket to be outward and away from the combustion chamber thus increasing head gasket life.The wire ring is'nt directly exposed to these high temperatures so head gasket life is extended.

I've observed the difference between the felpro and victor reinz brand head gaskets for the 5.7 diesel and the victor gasket is much more impressive.The felpro wire beads are thin and not secured all that well in my opinion.The victor gasket has a much wider designed wire bead so thats the gasket I would recommend.

A big thank you to burnkat for creating this thread.A great idea indeed.

Does the wire bead in the gasket require machining of the block?

No thanks needed to me-- it's all cut and paste-- most of the information is coming from you, it seems

Originally Posted by burntkat

Does the wire bead in the gasket require machining of the block?

No thanks needed to me-- it's all cut and paste-- most of the information is coming from you, it seems

The victor .010 thicker/.030 overbore gasket is normally used with engines that have a machined deck surface because of additional piston protrusion above the deck of the engine block.But I also use this gasket if the head surface has been machined as well.I've also used this gasket on engines with no decking of the block ever taken place,but the heads were.I use this type of gasket to compensate for any material taken off the heads or engine block.

let's say I have no machine work to the head or block. What gasket would you suggest in this case?

Originally Posted by burntkat

let's say I have no machine work to the head or block. What gasket would you suggest in this case?

Since the olds diesel has such a high compression ratio of 22.5:1,the .010 victor gasket can still be used since its thicker than std thickness gaskets and this of course will lower the compression ratio just a tad and that will add to reliability.

Burntcat,I bought a '79 Cutless Salon(ugly) 260 V8 in '84,and drove it 'til '89.
Put many miles on it,a lot at 80-90 mph and 25+mpg.Great engine,when running right. I also got a great education,suffered all the problems,and now know my diesels better than most.Blown head gaskets everytime you lose coolant,early IP pumps part disintetgrates and clog the fuel return check valve,sock filter in the tank clogs up,fuel gels on real cold days etc.I knew enough to keep the oil clean,and never had any bottom end problems.I hung it up when the oil pump shaft rounded off inside the vac pump drive gear,and I had to pull the engine to replace it.Too much $ and work for gaskets,bolts etc.to get my money back in fuel savings,BUT the main and rod bearing inserts and journals looked like mirrors,no wear on the cam lobes or lifters,and no ridges in the cylinder bores.Way over 100K miles.That sold me on diesels.I have a '95 Chev.6.5 TD now.Whole new set of problems.Oh well!

Thanks for the input.

I'll be rebuilding my IP, and I personally feel that anyone that runs a diesel engine and doesn't run bypass filtration is out of their mind. I run bypass filtration on everything I possibly can. Would love to run it on my bike, but there's just no room.

Notice I'm referring to bypass filtration in addition to fullflow. NOT a fullflow filter with a bypass in it which is designed to maintain flow to the engine should the FFF clog up. See the Motorguard filter on Ralph Woods' site for info- and realize that he's out of his mind with regards the price he asks. PM me for info on how to make one for about $30