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poolboy
11-18-2007, 05:05 PM
First, I've never owned a diesel truck before. I'm currently looking at a 2000 f-450 with 115,000 miles. They're saying that it is showing some "blow by", what is this and how concern should I be?

Looking Good Lawn Service
11-18-2007, 05:07 PM
it means that the truck is leaking oil and it doesnt drop on the ground but that when you drive it gets "blown" down the bottom of the truck, we had a similar problem with a rear main seal of the engine once.

poolboy
11-18-2007, 05:10 PM
it means that the truck is leaking oil and it doesnt drop on the ground but that when you drive it gets "blown" down the bottom of the truck, we had a similar problem with a rear main seal of the engine once.

Is this a major issue? Does this mean that the rings need to be changed?

P.Services
11-18-2007, 05:13 PM
lookin good have you ever worked on a diesel truck before?? blow by means the compression that should be in the combustion chamber is blowing by the rings and getting into the crankcase. the engine looses power and will not run to good. this happens when the tolerances between the rings and the cylinder walls have exceeded there tolerances. in short the engine is only going down hill from here so stay away unless you get a good deal.

P.Services
11-18-2007, 05:14 PM
it means that the truck is leaking oil and it doesnt drop on the ground but that when you drive it gets "blown" down the bottom of the truck, we had a similar problem with a rear main seal of the engine once.

i hope this was a joke!!!!

P.Services
11-18-2007, 05:17 PM
Is this a major issue? Does this mean that the rings need to be changed?

yes the rings need to be changed in order to repair this or you could continue to run the truck until it blows blue clouds of smoke because its burning so much oil. it could make it another 50,000 miles or another 500. you can do a in frame that means you repair this while the engine is in the truck by pulling the oil pan off and the heads. on the fords i believe your better off just to pull the engine and do it that way.

poolboy
11-18-2007, 05:35 PM
yes the rings need to be changed in order to repair this or you could continue to run the truck until it blows blue clouds of smoke because its burning so much oil. it could make it another 50,000 miles or another 500. you can do a in frame that means you repair this while the engine is in the truck by pulling the oil pan off and the heads. on the fords i believe your better off just to pull the engine and do it that way.

Thanks for the info. This truck (sale price $7000) won't be doing any type of work for awhile and will not be doing that much driving after it's up and going. Anyway, I guess I'll call the local shop to see what type of work estimate I'll be looking at.

desii
11-18-2007, 05:58 PM
it means that the truck is leaking oil and it doesnt drop on the ground but that when you drive it gets "blown" down the bottom of the truck, we had a similar problem with a rear main seal of the engine once.

Isn't that similar to a DRIVE BY?

A customer calls and you go to look at the job, when you get there you decide your not interested, so instead of stopping, you just DRIVE BY? :hammerhead:

We've had that happen once.....

Sounds like his mechanic can hear him coming...LOL

Looking Good Lawn Service
11-18-2007, 07:12 PM
briandennis1470 is also correct, blow by can result internally, causing higher oil consumption and a mess of unnessary problems, for a diesel to have that problem it must have been pushed hard, we have trucks with over 500,000 miles and never had that problem. however, as far as my previous answer that is not wrong either, just a possible different problem, I have seen what I mentioned called "blow by" at the peterbilt dealer all the time, tends to be the most common problem on big trucks, they leak a lil oil and it "blows" over the undercarrage of the truck as you drive, but you rarely see oil spots on the ground.

lawnspecialties
11-18-2007, 07:41 PM
First, I've never owned a diesel truck before. I'm currently looking at a 2000 f-450 with 115,000 miles. They're saying that it is showing some "blow by", what is this and how concern should I be?

"Blow by" is when you pull up to a new customers house for an estimate. The grass is a foot and a half tall with toys and an old car on blocks in the yard. They want you to "gimme a price on how much you charge?"

At that point, you immediately mash the accelerator on your diesel, never stopping, and just "blow by".

You guys don't know nothing about diesels.

:laugh:

poolboy
11-18-2007, 07:46 PM
"Blow by" is when you pull up to a new customers house for an estimate. The grass is a foot and a half tall with toys and an old car on blocks in the yard. They want you to "gimme a price on how much you charge?"

At that point, you immediately mash the accelerator on your diesel, never stopping, and just "blow by".

You guys don't know nothing about diesels.

:laugh:

Thanks for your input. MODS PLEASE DELETE THIS GUY'S POST.

LawnBoy89
11-18-2007, 09:38 PM
Why would you delete that I think it's hilarious.. Your question was already answered so what are you worried about?

lwcmattlifter
11-18-2007, 10:17 PM
Have you seen the truck running? How do the previous owners know the truck has blow by. More often than not if the truck is burning oil or smoking (blue) the injector o-rings need to be relpaced. It is normal to see some blow by from the crankcase evap system. I really doubt a 7.3 PSD needs rings at 115,000 miles.

GravelyNut
11-18-2007, 10:27 PM
First off, blowby is a normal thing to find on all Diesel engines. It is the amount of it that tells you when it has bad rings. A brand new Diesel will have a small amount. A well worn one will have a larger amount. Make of engine and equipment on it will also play a role. Is the oil consumption per 1000 miles excessive? That is a key indicator of neediing a ring job. Some makers will also tell you that a manometer reading on the crankcase pressure can be used as a guage. Detroit Diesel lists that spec in their manuals so that it can be monitored.. Without checking the books, I think that 1" of water was the normal reading when new

poolboy
11-18-2007, 10:29 PM
Have you seen the truck running? How do the previous owners know the truck has blow by. More often than not if the truck is burning oil or smoking (blue) the injector o-rings need to be relpaced. It is normal to see some blow by from the crankcase evap system. I really doubt a 7.3 PSD needs rings at 115,000 miles.

I'm checking it out this Friday. Thanks for your post. I just wanted to check with guys' that have knowledge of this type of motor. :):):):)

poolboy
11-18-2007, 10:32 PM
First off, blowby is a normal thing to find on all Diesel engines. It is the amount of it that tells you when it has bad rings. A brand new Diesel will have a small amount. A well worn one will have a larger amount. Make of engine and equipment on it will also play a role. Is the oil consumption per 1000 miles excessive? That is a key indicator of neediing a ring job. Some makers will also tell you that a manometer reading on the crankcase pressure can be used as a guage. Detroit Diesel lists that spec in their manuals so that it can be monitored.. Without checking the books, I think that 1" of water was the normal reading when new

Thanks, I'll keep that in mind. It'll be checked out by a local mech.

GravelyNut
11-18-2007, 11:17 PM
Have you seen the truck running? How do the previous owners know the truck has blow by. More often than not if the truck is burning oil or smoking (blue) the injector o-rings need to be relpaced. It is normal to see some blow by from the crankcase evap system. I really doubt a 7.3 PSD needs rings at 115,000 miles.
On a Diesel, 115,000 miles is just getting to its normal point. Shouldn't need them until about 250,000 if the oil is change regularly. A commercial duty Diesel engine should be good for > 500,000 miles. In industrial/generator use, engines run for thousands of hours before rebuilds. I've rebuilt DD engines that ran 18,000 hours between overhauls.

lwcmattlifter
11-19-2007, 08:39 PM
Keep us posted. Those 7.3's are hard to beat, especially for $7,000.

TXNSLighting
11-20-2007, 09:28 AM
blow by is nothing major. most powerstrokes do it. (this comes form a ford tech) you'll be fine.

lawnspecialties
11-20-2007, 12:45 PM
Thanks for your input. MODS PLEASE DELETE THIS GUY'S POST.

Lighten Up, Francis.:)

Dirty Water
11-20-2007, 05:29 PM
Blowby happens on all diesels when they are cold. Pistons and cylinders are machined with set tolerances to account for thermal expansion. During this warmup period, you will see blowby.

If you continue to see some smoke after the engine is at operating temperature, then your rings are failing slightly and you should have a mechanic do a compression test.

stroker51
11-21-2007, 12:16 AM
The easiest way to check for this is to pull the oil fill cap off while the engine is running and see how much smoke comes out of there. I read on dieselstop one time that on the 7.3's, if you just set the cap on the hole, not thread it in, and it doesnt get blown off, then there is nothing to worry about. It is natural for a diesel to have some blow by (smoke) coming from the oil fill hole when you check it, and for it to use a little oil, at 115,000 that truck shouldnt be needing too much done to it.

Snyderserv5060
11-21-2007, 12:55 AM
If you find out the compression numbers you will be able to determine if it actually is in need of rings or not. My call is not likely with 115k...that motor should have a lot of life left in it, being it 7.3 the truck should fall apart well before the engine goes out. Any records on it? Also read around on thedieselstop.com if you want to learn more about diesel Ford trucks.
You need to go see it run and make sure you take it out for a while to get the engine warmed up. As previously stated due to internal clearances until it warms up you may not be able to say it has too much blow by or not.

Travel'n Trees
11-21-2007, 04:21 AM
Blow by is common in the 7.3 Ford days sometimes due to dusting, a motor check the turbo and air filter. It happened to mine with in 3000 miles and one half a yard of dirt. I had to sell it and take my loses because ford would accept responsiblity for their poor design. Good thing I bought a duramx first it has over 200 k on it, It is helping me finish paying off my loan in 16 more months so I can afford to pay off my loses of a ford I only used one day for work.:confused: Sorry I know this will upset stroker51, But a small business financing Fords short cuts isn't a fun way to go.

mag360
11-21-2007, 08:21 PM
^^^^^^^^^He's still hilarious as ever^^^^^^^^:)

stroker51
11-21-2007, 08:56 PM
Travel n trees, you do your thing I'll do mine, you're not gonna upset me when I've got a combined 450+K on my 3 Ford Diesels, as I've said before I'm sorry to hear about your experiences with your truck, but that doesn't make them all bad, and dont bring up your TSB stuff, there are 2million plus 7.3's on the road, they can't all be bad.

Snyderserv5060
11-21-2007, 09:32 PM
<3 My 7.3 Powerstroke Diesel! Im sure if I get a 450/550 dump it will be another 7.3 PSD.

Cough cough, every powerstroke post on this damn site and he makes the same post... but oh well

Travel'n Trees
11-21-2007, 09:48 PM
Sorry I don't want others to have to be forced finance FORD's Company, like I am again for my second time because guys like you post that these trucks are great. Look do you realize the 7.3 is the same motor as dt444 in a international. Look at it's reputation, and add ford's short cuts what a combonation! Yes these trucks have ridicuolous amount of TECHNICAL SERVICE BULLETINS. Sorry if it offends you. Here I will mail my payment for a truck I haven't even owned for 2 years now.

lwcmattlifter
11-22-2007, 09:09 AM
Yes these trucks have ridiculous amount of TECHNICAL SERVICE BULLETINS.

This is true. Most probably don't remember how many problems these engines had when they first came out. The problems wer not as bad as the 6.0 but there were at least double the TSBs on the 7.3 than GMs 6.5 and Dodges 5.9.
I think it's really funny that this engine is now the reliable one compared to the newer diesels Ford is using. I really like my 97 PSD but if it ever goes and I decide to keep the truck a 7.3 won't be going back in.