85 6.2 diesel decision


Junior Member
I'm trying to decide if I should buy a pickup. It's an 85 GMC three quater ton 6.2 liter diesel. It has 140,000 miles, automatic, 4x4. It's a really nice truck prety good paint strait body nice wheels and needs new tires, plus verry nice sterio. But I've been told that diesel's are just big piles but this is a really nice truck. What do you think? It's my first truck and a dont want to mess up with this one. I will be going 4 wheeling, hauling a horse around, going to work and going to school. Maby somebody can give me some imput on the diesels. Thanks.


Senior Member
Lafayette, LA

I know a friend of the family with a 1984 Suburban with the 6.2L diesel and its great...nice for the few canoe trips I have been on with them in Missouri that 4wd sees some use....on the other hand I hear lots of other stuff about them that worry me including the fact that they use the same block as a gas engine on the 6.2L...meaning that it seems a bit risky to be running a diesel engine which has such high combustion pressures in a block made for gas combustion...dunno...still sounds nice though...I can almost kick myself right now because I passed up an 84 that sounds similar...just take a look around and use some instinct on where this vehicle has possibly been...you dont want to end up with the neighbors daily Mudder...best of luck


2000 Club Member
Ok lets put that rumor to rest. the 6.2 and 6.5 are diesel engines, not gas conversions. Look into the facts before you talk out of turn. Actually the 6.9 IH was originally a gas engine, but it worked ok for them. The gm diesel that was a gas conversion was the 5.7 olds engine.
With that year truck with the auto, is it the 700r4 or the TH 400. If its the 700r4 look to have a rebuild done before to long. If its the th 400 it will be much stouter and will mena you have the higher torque rated engine.
The 6.2 are good engines, if you do buy it, get a membership to the 62-65 diesel page.


OK, I have been a 6.2 fan ever since they came out. I worked on a ton of them in the military, and I have studied, rebuilt, modified and played with them for years.

The next person that tells you that the 6.2 has the same block as a gas engine, call them an idiot and question if their parents were related BEFORE they were married. Anyone who has ever made this statement has never seen a bare gasser block and a bare 6.2 block side by side.

So where did this rumor come from? Well, in the 70's, GM produced a diesel based on the Olds 350. Now, there is a difference between "based on a gasser" and "converted to a gasser." The Olds diesel was BASED ON the gas motor, but was not a gasser converted to a diesel. Before anyone disputes this, look at an Olds diesel block next to an Olds gas block (better yet, weigh them). There is alot of extra metal in the diesel block. However, it shared alot with the gasser- dimensions for one thing. It is easily possible to convert an Olds diesel to a gasser.

Now, GM had terrible luck with this Olds diesel- mostly because America wasn't ready to accept diesels, but alot had to do with it's gas motor roots and a company inexperienced with diesels. But with a little work, these diesels still make "decent" motors.

On to the 6.2... This is not the same engine as the Olds, and DEFINATELY not the same as a gasser. The 6.2 has its quirks, but so does any other motor out there. I love these 6.2's and the 6.5's. They are powerful, reliable, and fairly cheap to repair/upkeep.

I think if you are going to be pulling horses around, you will be very happy with a diesel. They do well off road too, but keep in mind, you don't want to unwind these engines like you do a gasser. Diesels can make twice the torque at half the RPM's- they are monsters in the low to mid RPM range. But if you have a habit of winding a motor to 8 grand very much, you won't like the results.

Simple rule to follow- if you like reving the motor and acting like a race car, go with the gasser. If you like alot of pulling power and decent mileage and dependability, the diesel is your ticket. I'd say go for it- only you will know if you will like it. If not, it wouldn't be hard to sell.

John DiMartino

PlowSite.com Veteran
Psyclopse,my uncle has an 84 6.2 diesel K30,I plowed with it for 5 years.it has a 4 spd manual SM465,and 4.10 gears.I dont know what you consider to be powerful,or torquey,but trust me this and other 6.2's i ve driven cant even getout of there own way.The 1 ton is downright dangerously slow when ther blade is on and V-box is full.As far as rev it out-you must wind it right to the max in order for it to pull the next gear,even on flat ground.I am guessing,but id say a 4.3 v6 would flat smoke this thing in the same truck,while turninmg less RPM's.In a 1/2 ton or 3.4 pickup,maybe the perfromance would just be poor,mbut thats not good enough for me.The 6.2 has been a great engine for him,its tired now,it has 65K farm truck/plow truck miles on it(probably 8000 hrs+),since it is always left runningthroughout storms,even overnight.In 93 it ran for 5 weeks straight during the cold snap we had,he just added 2 qts of oil a week to be safe.Reliable-yes-powerful-torquey-never


Are you saying that (for instance) from a dead-stop take off, the truck will wind up (RPM-wise) before it shifts into the next gear? That's what I got from (the middle) of your post, but maybe I am not understanding right.

At any rate, I bought my 88 GMC 3500 last spring. It was purchased new by an older local gentleman who only used it a few times a year to pull his boat to the reservoir. When he sold it to me, the thing had only 55k original miles on the whole truck. Believe me, you just don't see an 88 GM truck around here with the cab corners still solid. This truck was pampered.

At any rate, when I got the truck, it would really rev up pretty high before it would shift. I had complained about it alot, but always had too much going on to mess with it. I lent it to a buddy (who works at a GM dealership) to move with, and he adjusted the cable that controls the shifting. Now it shifts like a normal truck. This could be what is happening to the 84 you mentioned.

I don't know, my experiences with this moter have been positive. My diesel will plain out-push and out-pull any of the gassers I had lately (however, acceleration is NOT a strong point). I have been happy with the power of these engines. I know some of the other diesels (Cummins, PowerStroke) are alot more powerful, but heck, the 6.2 is easier on the wallet to repair.

I still stick to my opinion for this thread- buy the truck if it is in good shape. If you don't like it you can 1) sell/trade it for a gas truck or 2) put a gas motor in it.


Junior Member
If the price is right and it appears to have been maintained properly, I'd say go for it! I had been looking for a nice diesel PU under $6000 for years. I recently purchased a clean 83 Chevy G20 conversion van with a NA 6.2 diesel, 106,000 miles for about $3000. I absolutely LOVE it! Even with a 4.10 rear end, I'm getting around 20 MPG on the highway. It has terrific acceleration and will easily "keep up with traffic". Ownership has been less scarry since I joined The Diesel Page. http://www.62-65-dieselpage.com/ Tons of tips, info, troubleshooting, etc. Membership is about $20 /yr and is way worth it (I've probably saved 5 times that already in repairs / troubleshooting).


I haven't joined The Diesel Page for the simple reason that the pay-for-membership websites are out of style. That's just not what the net should be about. Once, I had considered joining- they had enough free info to give you an idea as to what may be inside. Now, there is next to nothing for free there- you would have no idea if you were paying for crap or not. And if you weren't satisfied, I doubt they'd refund your money.

I posted a simple question on their board once- I asked where I could get info or a wiring diagram. I was pretty much told that my post was out of line and I'd have to be a member to get info like that. Then, the thread disappeared. Yea, that made me want to join. Besides, what I hear, most of the really good info comes from the message board there- so I have to pay to see someone's advice- someone who also had to pay- the owners are making money from the work of others.

I'm sorry, I can go to Chuck's Chevy Pages and get a ton of info for free. I don't know if he has a membership there, but there is enough free info to keep you busy for weeks- you'd know what a membership would get you. As far as diesel-only sites go, I'd like to see http://www.gm-diesel.com/ flourish instead- it's free. They have the drive, they just need the visitors and people to contribute their knowledge. Also, The Diesel Page didn't want to trade links with them because they didn't want the competition- especially from a free site.

I don't recommend paying for a site unless you have money to burn.


PlowSite.com Addict

I kind of agree with your view on a free internet, however its just not possible. Jim Bigley, owner of the diesel page, is not getting rich on this. Yes he is making money, but it takes money to get money. His expenses are immense. is $15.95 too much to spend for a wealth of info? 4.3 cents a day!!!! If thats money to burn, then I must be a billionaire!! I dont think its out of style. No, your not paying for crap there. Diesel Page members are a very tight knit group (close to 6000 members) that actually meet at a yearly get together. Their forum is a wealth of knowledge and has helped many. Where does the knowledge from this site come from??...US

I tend to get upset when someone spouts off negatively about something that they have not tried. No one is pulling your arms off asking you to join. Its just that when you are asking diesel related questions in here (that may or may not be answered correctly), in the DP you have a much broader base of "experts" to help you out.

Believe me, if there was something negative to being a DP member, your negative views of the DP might be supported by others here.


2000 Club Member
Here Here Tom,
I to am a member of the diesel page, I have the window sticker to boot. Just with the little things that I have learned from the newslettrs and forum , I have saved the 15.95 over about 100x. SO heres to Jim and the GM diesel page.


I am not saying that the site is crap. I am not speaking negative of the site, but rather I am speaking negative of paying a membership. If there is good information and/or experts there, fine, you may have saved your membership fee in advice and tips.

HOWEVER, I don't subscribe to the "we need the money to keep the site going" theory for a good reason. I have been to many, many large sites (various topics) that publish articles, host chat rooms and message boards, etc all while still being free for a visitor to check out. There are many other ways of generating revenue- even the DP would have a larger group of visitors if they didn't have to pay for access.

dixie, you said that you tend to get upset when someone spouts off negatively over something they have not tried. I agree with that, but look at it from my point of view- I went into the "free" section of their message board. I posted a question- NOTHING I read stated it was wrong to do so. I was quickly told that I could not ask that question unless I was a member. SO I DID TRY IT OUT. There has got to be something "real" there to make me think I'd get my money's worth. Instead, the impression I got was that I wasn't a member, so I didn't deserve an answer. If my question would have been answered, I would have considered joining. Don't be mad at me for my opinion and first impression. Amazon, Microsoft, Ebay, etc, etc, etc ALL want your money for a product or service, but they provide you with enough FREE info to entice you to give up your money.

Also, it doesn't have to take much money to run a site such as DP. DON'T let site owners fool you. I have a couple associates degrees in the computer field, so I know what it takes. Unless DP has their own servers and their own high speed connection, it wouldn't cost much. Of course, I'm not saying that they don't have their own servers or high speed connection, so it is possible that they have higher costs. I am curious though if the fees from 6000+ members are reported at tax time (legally, you members have a right to ask for proof of this).

Tell you what, since I haven't ever been in the famed "members section" I have to admit- I may be wrong and there may be that Holy Grail of info that I've been looking for. If all the members feel that strong for this site, I'll make a deal: Just ONE of those 6000+ foot my membership fee and give me 15 days. If I find two particular pieces of information that I need (that a site like this SHOULD have) and I'll pay that member DOUBLE. One item is electrical related and the other is suspension related. So, before everyone decides to hate me for my initial opinions so far, lets see someone step up and put their money where their mouth is.

(I'm NOT trying to start an argument, really. I am just stating my opinion of that site based on what is there for the non-member, and how I was treated on the message board. Anyone who reads this and I are two different people, and most likely both adults. Our opinions can differ and we can still be friends...)



It has been said that the DP isn't making alot of money. Allow me to illustrate...

$15.95 (membership fee) X 6000 (actually 6000+ members) =
$95,700 yearly.

Expenses? Sure.
Domain Name registration is $150 to set up and is good for 2 years. It's $50 each year after. I'm sure they've been around at least 2 years, but I'll allow the $150.
$95,550 remaining.

Say (for instance) that they used ProHosting for their server provider (which I doubt). ProHosting's "plan C" offers unlimited space, multiple emails, all the bells and whistles you want for $100/month. Unless you have alot of money to invest in your own servers and high speed line, you'd be stupid not to use a hosting service. Then again, the point I am making is that there IS a lot of money being made. $100/month=$1200/year
$94,350 yearly left.

Sure, there are other things that take away from the amount, but there are plenty that add to it. Keep in mind that this big number most likely floats towards $100,000 yearly once all is figured and accounted for (unless this money is being invested, which adds even more). In 5 years, a half of a million is made- invest wisely and play your cards right and you can turn this into a million QUICKLY.

Now, sure, there was some trip or event or something- do you really think it cost $100,000 to do? No, most likely it didn't cost the DP anything- that's what sponsors are for.

Again, I'm not saying it isn't a good site. I'm not saying anything at all negative except that the membership fee isn't rational when they don't let the potential member know what they're getting. Notice I didn't scoff the membership altogether. As I mentioned before, Chuck's Chevy Pages has a ton of info I can get to and look at for free. With that much free info given to me, it would make me WANT to pay to see what else there is. Get to a site where there's NOTHING free and I move on- I know the info I am looking for will be elsewhere on the net.

While a DP member doesn't like it when a negative thing is said about the DP, I don't like it when someone says an entity that brings in close to $100,000 yearly with little overhead isn't making money.


PlowSite.com Addict
Here we go beating this dead horse.

Psyclopse...do you only have one eye? Open the other eye and look under your couch, under the seats on your trucks, in the washing machine, pay phones, soda machines, etc. Add all this money up and I'll bet it is more than $15.95. If Chucks Chevy Pages has a ton of info, then the DP has 10 Ton of info, plus its geared just for GM diesels. No offense to Chuck, I personally love his pages and learned a lot, however, the diesel section (is there any?) is small.(Sorry Chuck) The DP has no sponsors or banners anywhere. Yes, I guess $94,350 a year is a profit, a BIG profit? That depends on what you consider a lot of money. You happen to think $15.95 is too much money, so maybe your views here are a bit skewed.

Anyway, If you join and are not pleased with the results (doubtful), why not ask the $94,350 man to refund your $15.95? E-mail Jim himself and ask him questions about membership. I don't even own a diesel truck, and I find it informative for my truck.

Remember, I'm not the person wanting questions answered pertaining to my diesel truck, YOU ARE! Do what you see fit, spend it where you want. All I'm saying is that the DP is worth the money for a membership.

P.S. Are we still friends? :)


Sure, we're still friends. Just because we don't agree on a topic doesn't mean anything (if that was the case, I'd have to cook my own meals).

Anyway, as far as income, anything over $50,000 is alot of money to me, then again I have 4 kids and a bunch of trucks to maintain. Of course, if there is more than one person getting paid at DP, the more ways you divvy it up, the less each person gets. But if you are dedicated to a site, it doesn't require a bunch of people to run. Chucks can very easily be ran by (and most likely is) Chuck himself. Message boards are generally CGI (Perl) scripts that require little to maintain. Of course the more you know (HTML, Java, Perl, etc) the less you have to rely on outside help.

I guess what I am saying is with my education, I could manage a site 10x the size of Chucks with very little outside help IF I had 3-4 hours a day extra to maintain it (of course creating the site would take more time). What I am getting at, is that it is possible for one person to be running the site, thus pocketing the money after expenses- that comes to an income that is much greater than mine. Is there a problem with this? HECK NO!!! If there are people out there that believe they are getting what they pay for, then the owner(s) DESERVE the money they are making.

My whole point is this- there are a bunch more people out there (like me) who have to have an example of what they are going to get before shelling out the cash- even if it is a mere $15.00. I have 2 kids in diapers, 1 in pull-ups, and one who constantly "needs" more and more expensive toys, cloths, etc. So, even the change under my seat gets collected for this kinda stuff. My trucks are aging, needing things often, and they're not all GM diesels. It is hard for me to part with even $15 sometimes. It is nothing against you or the DP owner(s), but even my best friend of 20+ years can tell me how good the DP is, but if I can't see it for myself, I can't justify paying for it. To me, it is like buying a car sight-unseen. However, I also believe that I shouldn't ask for my money back if I were to join and not be satisfied. If there isn't a stated money-back guarantee, then I am paying for "as-is." I don't mean that in a bad way, what I mean is the DP says "here's our site and here's our price" and I say "ok, here's the check" then they held their end of the deal- they offered their content, regardless of if I liked it or not. I don't think it would be fair to ask for a refund after I have seen the info.

There are alot of people out there like me- a lot. How can the DP reach these people? Simple. They can 1)Add more info out front that the casual wanderer can get to for free. Keep the real good stuff inside under membership. 2)Post articles in the free section that are generalized, but good. For instance, an article on how to instal a turbo on a 6.2- tell about the pros & cons, GENERALIZE installation, etc (a typical magazine article), then at the end say something like "A more detailed look is in the member section" or "Photos and step-by-step in the member section." 3)And this is the best- offer time-limited trial memberships. This way, a potential member may look around the actual site to see for themselves. Of course they can be restricted in various ways- read-only on the message boards, etc. This will give the person like me reason to want to get in. Like I said, there are alot of others like me, and I could see the DP membership growing even more by reaching these people. It's hard to want what you do not know exists.

I will have to admit something right now though- you say that you DO NOT own a diesel and you say you feel you are getting your money's worth. Well, that is sinking into my head, and with that sentance alone, you have had the greatest positive impact on me in favor of the DP so far.

Answer me these questions (yes or no is fine, don't send me material from DP or post details that I should be paying for)...
1) Are there wiring diagrams available, most importantly, under-hood wiring, that is good enough for me to diagnose a harness problem with?
2) Is there detailed suspension information to help me work on the IFS?
3) Is there "parts interchange" information?
4) Are there detailed year-by-year specifications as to what engine, tranny, axle, etc. options were available?

If at least half of those questions can be honestly answered with a "yes" then I will have to admit defeat, join DP, and repent on this and any other message board.


PlowSite.com Addict

1)I haven't seen any wiring diagrams per say in the DP, however, I havn't been looking for any either. They may be there. A very good source for wiring diagrams is available in The Chevrolet C/K Pickup Electrical Diagnosis and Wiring Diagrams Manual that is available from GM (back of owners manual is ordering guide). Mine came with my Parts and Service Manual. It has 149 BIG Colorful pages of nothing but wiring diagrams for every inch of wire in the 1990 (my year) models. Yes it even includes a diesel section. The whole set was like $150 or something. Well worth it.

2) There is a current article in the members section detailing the 88-99 K series IFS front end rebuild. Pretty detailed, though not precisely step-by-step. Covers all bushings, ball joints, steering joints, etc. Nice article. Again this is all available also in the books I mentioned above.

3) Sure they document many very detailed conversions: 6.2NA to BANKS Turbo, 6.5 NA to Turbo, 6.2 NA power mods, etc. Tons of stuff here that doesn't really intrest me per say. They also have a trouble shooting guide that lists lots and lots of problems and their many causes and how to remedy these. This is where it will save you big $ on diagnosis.

4) Yes, thats in there and is really everywhere, iv'e seen it in books and magazines lots of times, but as I said, yes its all in there. Most of the files are pdf (acrobat) type so a long download then you can flip through them all. Also, this is available if you want a super membership. Then all the articles are mailed to you and every time a new one is published, its in your mailbox. Don't remember the price on that option though.

The DP can't really compare to CCTP (Chucks) as they look and act totally different. Again not to down Chuck, the DP has 10-20% more content (articles) and that doesnt include pictures (lots).

Hope this helps.