What did you do with your GMT400 today...or yesterday....

[dbrannon79]

This afternoon I got time to finally fix the leaking crossover. Pulled it off and first thing I did was check the bolt holes in the heads. Come to find out all four holes were half full of old "the right stuff" sealant. I spent a good amount of time with a pocket screwdriver and a small pic getting ti all out. test fitted the bolts into the holes and they were able to tighten down without the need of the washers.

How much of this sealant does one have to use to get the bolt holes half full of sealant?? I also made two gaskets from some material I had since after cleaning the surface of the head and seeing it slightly pitted. buttoned it all back together, filled with water and seems to not leak anymore!

I still need to do a complete flush, but I wanted to get this truck running before I do anything else.

Here are some photos of the aftermath from what I found causing the leak.

 

[dbrannon79]

I also recorded a video of it running while looking for leaks. the reason I did the video was I had thought about showing how the blowby is on the engine.

Here it is in all it's glory. tell me how bad this looks!!!

 

[Will L.]

In post 4400 when you started- I thought ‘silicone?’ But in paragraph two you said fresh scraped metal. I thought you meant you saw bottom of a hole where the bolt was hitting metal ….
Silicone makes sense and looking at the bottom couple threads on that bolt, metal shavings make sense. That bolt should be in the trash can. Im afraid the threads are slightly damaged in the head too. But it it’s all holding together now, don’t mess with it. My buddy Charles says “the enemy of good is better” meaning if it works don’t fix it and don’t get carried away trying to make everything into perfection. The silicone filling the hole caused the bolt to strip in the threads slightly hence the metal you saw.
If ever dealing with this and the surfaces have a hard time sealing making a sanding block with a milled surface or glass pane glued to wood block then covered in 2000 grit paper - that how to diy surface things. But that rarely needed here. Usually that the aluminum side from pitting caused by needing an anode in the system.

On the blow by- yeah that’s a descent amount. That cko provent isn’t doing it’s job. Is plumbing right? Is that the steel filter in there? It should be no smoke coming out of there at all at idle. You’re still burning a descent amount.

And oh yeah- how the heck did that dude shove that much silicone to the bottom of the hole?!!

 

[dbrannon79]

the CKO provent still has the steel filter, it is also wrapped with a double layer of used clothes dryer sheets. the material used in the dryer sheets seems to resemble what is used in these CCV filters very closely. the week before the trip to the coast I had mentioned reversing the in and out connections to see what would happen since it doesn't have a valve in the outlet. I had switched them and noticed the soda bottle tied to the frame filling faster now.

thinking about the real provent filter I started thinking about how much oil is being sucked out of the engine and was afraid that the real filter would get saturated and clog. since switching the inlet and outlet hoses that random loud clatter / rpm blip has not happened. I have a feeling the engine was choking on it's own oil. That filter runs about $60 too!

 

[dbrannon79]

Something that dawned on me.. watching my own video I noticed that when I accelerate the engine, the blowby almost goes completely away. I assume the turbo is spooling up and is sucking all the crankcase pressure out. I am wondering if by slowing down the flow from the crankcase the oil loss would decrease some. teeing off from that 1 inch hose so the turbo + CKO provent is pulling from not just the valve cover but two locations on the engine at the same time might help.

it might be worth a try. I have been thinking about working with the 6.2 engine and see if it will be any better to go into this truck. then maybe use this 6.5 engine for a rebuild candidate.

 

[Will L.]

Yeah the real provent is pricey- have to weigh it against cost of oil.
The real filter shouldn’t plug up- it will simply fill your bottle faster. Remember the provent doesn’t cause the oil to leave the engine, it just helps catch it so you can pour it back in.

Yes the higher engine rpm is making the turbo and intake of the engine suck in more of the oil mist. The idle rpm doesn’t pull enough vacuum to suck in the oil mist.
If you rev it up with the hose off you’ll see more oil come out of it.
How you had it off and was plugging it with your thumb- just having it off is what is meant by “vent to atmosphere”. This is an easier solution than a catch can but not always police, epa, tree hugger friendly- and also means you buy oil more frequently.

In theory- you could add a pressure gauge to your valve cover. Any pressure is bad, vacuum is good. Stuff the hose from the valve cover to the provent full of stainless steel mesh. That helps capture the oil vapors and coalesce the oil into liquid and return it to the engine if the hose is running uphill like a drain. But the more restrictive means more pressure in the engine which is bad. So through experimenting you learn how much you can add without causing issues.

If you always ran you a/c and had an a/c inner cooler made from a rear air condenser that the hot oil mist went across (like a water to air heat exchanger) the cooling would help coalesce (condense) the vapors back to liquid and drain back to the engine. Not practical but just sharing the theory of how it works.

Create the optimal resistance to slow the oil and give it media to collect on. Dropping temperature helps but getting it cold enough fast enough is insanely difficult.

 

[Will L.]

Oh yeah- don’t think that amount of blow by is an engine killer. They get way worse than that and still run a long time. Just makes a messy truck and higher mpq cost- miles per quart of oil that is. Some folks don't have smog in your area and just keep adding oil at every fuel fill up.

 

[dbrannon79]

I'm curious about the steel mesh. Chris had mentioned about the mesh that lives in the valve cover. I preceviably can't really tell the difference on the amount of blowby from this engine vs the 95 just looking at it other than this one drinks the oil LOL. you make me think wondering if the mesh has been pulled out of the valve cover at some point in it's life.

 

[Rutjes]

I also recorded a video of it running while looking for leaks. the reason I did the video was I had thought about showing how the blowby is on the engine.

Here it is in all it's glory. tell me how bad this looks!!!

Looks exactly like mine. Truck has plenty of power, even when towing heavy. I don't really worry about it. Only one minor issue I have is starting. I think it should start faster, but I blame that on the AC60G glow plugs. I think the extended glow time modification will fix that.

I'm thinking about getting a ProVent² 200. One of my part-time employees also works at a mechanization parts supplier, maybe he can get me one. They are hard to find online over here. He will let me know next Tuesday.

 

[Will L.]

Looks exactly like mine. Truck has plenty of power, even when towing heavy. I don't really worry about it. Only one minor issue I have is starting. I think it should start faster, but I blame that on the AC60G glow plugs. I think the extended glow time modification will fix that.

I'm thinking about getting a ProVent² 200. One of my part-time employees also works at a mechanization parts supplier, maybe he can get me one. They are hard to find online over here. He will let me know next Tuesday.

What starter are you running? The power master 9052 (especially if you upgraded battery cable size) gets a lot faster rpm crank speed. This makes for a lot more heat and easier & faster starting.

 

[dbrannon79]

I recently noticed starting issues on this one. it still has the factory style starter but has upgraded cables. I think the starter is wore out though. when hot I get the "click click" before it cranks. today I was leaving the house and noticed I had to do a slightly longer crank cycle and it seemed to crank slower than usual. I'm considering the powermaster for this truck too. I put one on the 95 and it cranks like there is no tomorrow!

the current starter is painted black with oil so I want to attack some things up top before doing the power master. I want to pull the intake and replace all the rubber fuel lines under it, might as well do valve cover gaskets too plus check the rocker buttons (install bolts and nuts). Not to mention do away with the cam sensor since it's seeping oil from the connector too.

@Rutjes this one has plenty of get up and go power too which baffled me as to how smooth and good it runs with the amount of oil I am loosing. I'm loosing a full quart every 200-300 miles. partly from leaks but most is getting drank. the valve covers and cam sensor leaks are visible due to the block covered with wet oil along with the starter painted wet, but it has not left any spots on the concrete in the last month or so since getting on the road.

 

[Rutjes]

What starter are you running? The power master 9052 (especially if you upgraded battery cable size) gets a lot faster rpm crank speed. This makes for a lot more heat and easier & faster starting.

I have no idea what is under there. Definitely not a Power Master though. I did upgrade the cables. I made my own using 35mm2 and 75mm2 wire. I know it started better after that upgrade. I can't remember when I changed the glow plugs and when I did the cable modifications. I think I replaced the glow plugs after the cable upgrade and starting got slower after. I have a couple different resistors laying around in the center console ready to try the extended glow time modification.

Don't get me wrong, it is starting OK, just not great.

The Power Master has been on my wish list for a while now, but I think I'll wait until I can drop in one of my Optimizers. Before I drop one of them in I want to invest in other upgrades for it as well. Some parts I have already sourced. Like ARP studs, HX35 turbo, HX35 install kit, high flow water pump (got it from TSP), HD fan clutch and a Duramax fan. Sourced my own set of valve cover studs. I might have a valve cover "girdle" cut or buy one from Leroy or Quadstar by the time I get to it. I'm just waiting for the right moment, financially. Other things on the wish list include a Fluidamper, TSP's halo girdle and a bunch of other goodies.

@Rutjes this one has plenty of get up and go power too which baffled me as to how smooth and good it runs with the amount of oil I am loosing. I'm loosing a full quart every 200-300 miles. partly from leaks but most is getting drank. the valve covers and cam sensor leaks are visible due to the block covered with wet oil along with the starter painted wet, but it has not left any spots on the concrete in the last month or so since getting on the road.

When I mentioned towing, I was talking about 15000 lbs by the way. I know, way too much for a 6.5, but still, no problem for my truck. Plenty of get up and go power. Doesn't even break a sweat (high flow pump, HD fan clutch and Duramax fan installed). Sure, I won't keep up with normal traffic at the stoplight, but that's to be expected with that kind of weight behind it. I don't tow those kind of weights often by the way. I have my Ivecos for that. Besides beeing my daily driver, the truck is also my emergency backup vehicle incases one of the Ivecos is out of action.

I should start keeping track of the oil consumption, see where it's at. I THINK I finally fixed my leaks by resealing the oil pan and the front main seal.

 

[Will L.]

Ok makes sense. Yes the 60G is slower, but you have to think of it as exchanging time each morning started for the amount of days lost from internal engine damage the other glows can cause.
Or like knowing you are on long trip and you can go double the speed to get there but if caught going that fast you go to jail and definitely loose more time.
For now it’s worth just turning the key off then back on again for a second glow.

 

[Rutjes]

For now it’s worth just turning the key off then back on again for a second glow.

That's what I have been doing most of the time.

Right now I'm getting the truck ready for the yearly inspection. Should be road legal again next week. Hopefully some day soon I will find the time to try the resistors. I can't remember the values, but I have a couple of different ones to play around with.

Oh, does anyone know of a post where someone mentioned resistor values and the amount of seconds they extend glow time? I know it is out there, but I can't find it now...

 

[dbrannon79]

@Rutjes what resistor are you referring to? for the PMD? I know there was a post long ago about using a resistor inline between the PCM and the glow plug controller. I tried that on my 95 before re-programming the PCM. I had absolutely no luck getting it to work. what you can do if you want a manual button in the cab is tap into the yellow wire on the controller (if you have the 3 wire one) and run that to a push button switch. the other side of that switch would be a positive from your fuse box preferably from a keyed source. when you push the button it will energize the controller giving you a manual control over it while keeping the ability of the PCM also controlling it.

I can't remember if a one way diode is needed to be installed between the wire from the PCM and the controller so when you use the button power isn't fed to the PCM too. Probably would be a good idea and wont hurt anything.

 

[dbrannon79]

Today I removed the white camper shell from the 93 and found a soft top bed cover. it's made for a GMT400 6ft box but as it was new in the box and cheap I went for it. Got it installed and it looks great, much better than that old camper that stuck out over the sides of the bed. I also was getting tired of crawling on my hands and knees to get something from the forward area of the bed. with an 8ft box that is a long ways to crawl and my knees were hurting by the time I crawled in, still having to crawl back out LOL.

I want to take cut some plywood and make a section up front with some access doors like you find in boat floors to get at the front of the bed.

What says you all?

 

[Rutjes]

@Rutjes what resistor are you referring to? for the PMD? I know there was a post long ago about using a resistor inline between the PCM and the glow plug controller. I tried that on my 95 before re-programming the PCM. I had absolutely no luck getting it to work. what you can do if you want a manual button in the cab is tap into the yellow wire on the controller (if you have the 3 wire one) and run that to a push button switch. the other side of that switch would be a positive from your fuse box preferably from a keyed source. when you push the button it will energize the controller giving you a manual control over it while keeping the ability of the PCM also controlling it.

I can't remember if a one way diode is needed to be installed between the wire from the PCM and the controller so when you use the button power isn't fed to the PCM too. Probably would be a good idea and wont hurt anything.

Inline between the PCM and the glow plug controller. I'd prefer that over a manual button. Re-programming the PCM has crossed my mind, maybe if I ever decide to get a tune. Probably not, I'd rather put the money into a DB2 conversion. Shipping the PCM to and back from the US will probably cost as much or more as the re-programming/tuning and with the DS4 being discontinued it seems like a bad investment to me.

 

[Will L.]

Inline between the PCM and the glow plug controller. I'd prefer that over a manual button. Re-programming the PCM has crossed my mind, maybe if I ever decide to get a tune. Probably not, I'd rather put the money into a DB2 conversion. Shipping the PCM to and back from the US will probably cost as much or more as the re-programming/tuning and with the DS4 being discontinued it seems like a bad investment to me.

If anyone knows how to get ahold of Kojo- he is supposed to be the best 6.5 turner on the planet and lives in the EU. Sweden iirc

 

[dbrannon79]

@Rutjes What year is your truck? if OBD1 I can send you a copy of the tune I did for my 95. all you'll need is a blank prom chip and a programmer. I think I spent around $80 for what I was able to get from Moates before they went out of business. The tune I did only addressed the glow plug time plus a little more fuel past 50% throttle.

 

[Rutjes]

If anyone knows how to get ahold of Kojo- he is supposed to be the best 6.5 turner on the planet and lives in the EU. Sweden iirc

A quick Google search only comes up with very old results. If anyone knows how to get in contact with the guy, I'm might give him a try.

@Rutjes What year is your truck? if OBD1 I can send you a copy of the tune I did for my 95. all you'll need is a blank prom chip and a programmer. I think I spent around $80 for what I was able to get from Moates before they went out of business. The tune I did only addressed the glow plug time plus a little more fuel past 50% throttle.

It is a '98. So, ODB2 unfortunately.