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Opinions needed - Performed Optical Bump

So temp gun is showing you 178 but it doesn’t open until 185. Kinda shows how temp guns don’t show the temperature the critical part of the engine is dealing with. I have no doubt your temp gun is accurate- about 10° drop through the iron is normal.
 
@Will L. I never thought of of that way, but very true. the outer metal temp will always be lower than the coolant inside!

thinking about this actually scares me lol I had used the temp gun the other day just to see what I was at before and it was reading 196 or so on the water outlet. that would mean I was actually running close to 210 with the gauge just a hair over the 1/4 mark then. that's more proof the factory gauge cannot be trusted!
 
WarWagon said:
Take the old fan and clutch with you. Store it spring down. Just in case you need it.
Click to expand...
I have it in the back of the truck standing up in between the bed and by toolbox along with a spare alternator, "dead but still runs" PMD, 4 gallons of water and a gallon of oil! Hopefully I won't need any of it, but ya just never know.
 
Good morning guys! I drove to work this morning, first drive with the new 180 t-stat installed. it took a lot longer for the truck to start moving the dash gauge! I probably got a good mile n 1/2 down the road before it started to move. it came up to just below the 1/4 mark on the gauge and stayed there, so it's defiantly running cooler. I was afraid that it wouldn't shift into overdrive when I got up to speed with the temp just beginning to rise but it shifted fine :)

it would be nice if there was a way to re-calibrate the gauge so it could be somewhat trusted. one of these days I may get a new sender and try a hot plate with water watching it at various temps. Only I cant think of a hot plate that would get water up to 260 degrees to try and max out the gauge!

something that I was wondering on the thermostat and water pump design. does anyone know what the purpose is for the spring loaded block-off disc is for on the bottom of the stat that blocks off the bypass hose coming off the pump in the bottom of the t-stat housing? it would seem to me that if that ever opened it would lower the flow through the heads and block causing the engine to get hotter!
 
That is a bypass valve on the thermostat.
Engine cool: The thermostat is closed& bypass open so the waterpump is pushing water through the engine block, then heads, then to thermostat, then down past the open bypass valve into the waterpump and back into the block. Rather than all the water sitting still and the waterpump blades just creating turbulence in there, it helps get all the water up to the same temperature and is removing the heat from the heads and cylinder walls.

Now the water is hot enough to open the thermostat & close the bypass valve. So none of the already hot water goes back into the waterpump or engine, it all goes to the radiator.

There are systems that dont have the bypass valve. Some simply stop the flow of coolant. This is the worst because it causes massive cavitation in the waterpump eating up the metal. And not actually circulating the water through the engine well means the water against the heads and cylinder walls will be much hotter than the water at the thermostat so by the time the thermostat opens at 190, heads are at 220 and cylinder walls can be 210.

The dual thermostat housing doesn’t use them, but to fight the problems above, they have a constant bypass. This has a different bad effect of once the water is hot, a certain percentage of the already too hot water is going to go back into the waterpump and through the engine! So it immediately heats up the incoming cold watercoming from the radiator, and can not remove a lot of the heat it should from the radiator.

Many people did their own testing- and learned the single thermostat housing with the block off is superior cooling. It’s funny to me because if you think about the design flow of the waterpump- look at upper and lower radiator hose sizes. That is what the pump flows by design. The thermostat bypass should be the same size on all 3 ports- incoming, bypass and out to radiator. This would keep flow at an equal volume and eliminate pump cavitation. Talking to a couple auto engineers about this one time, and they both agree EXCEPT fitting the other large hose becomes cumbersome for what is usually not a manor issue. Most waterpumps are fully housed-unfortunately not ours.
Of all the work done to make this diesel basically fit like the big block and small block chevy platform- the dumbest thing they did was not use the same exact waterpump design and have the timing cover separate from the waterpump. SMH.

oh, duh! I nust remembered there is a YouTube video showing thermostat bypass... i will post it.
 
this is good info! I was literally thinking about looking for a dual thermostat housing for when I do get a balanced pump and "true" fan clutch later on. Now I think I better stick with the single thermostat!
 
This is interesting, when I tested the 180 t-stat in the pot of water I didn't notice the bottom plate move any, only the disc that opens in the stat. or at least I didn't pay any attention to that. I am going to have to pay closer attention to that bottom plate and see if the one on my old one moves any when it opens.
 
BTW for my future reference, would it be worth the risk if later on.. when I go out to the junkyard to snag one of those 6.5 engines I found out there to have a block to take my time on and rebuild or refresh for a spare engine? I had priced it before to be about $500 plus what ever they charge to pull it out for me. both of the trucks I found already had the intakes removed but the IP and turbos were still there along with everything else from what I saw. I know the proper way to inspect them is by pulling the pan first, but I don't think I would be able to before paying them to pull it first.

Wrenchapart sends out text messages on weekend sales they have. every now and then they have engine sales with 20-50% off. sometimes they even have a sale all you can fit in a wheelbarrow for $100
 
YES on staying with single stat. Some time back I found and posted a company that makes billet cubes just to hold block off style thermostat and could connect with hoses for people needing the rare 96 style thermostat housing but cant find one.

Unfortunately cracked block main webs and cracked cylinder walls, cracked heads- is a risk you have to take on used 6.2/6.5. However- if you show up with a pizza for the guys and talk to the manager, who usually gets first slice, and tell him these engines are known for cracking - some junkyards offer “store credit” warranty. do this on a trip getting a few small things.

So buy the engine, they pull it and you pull the pan and heads off before you even leave. (Definitely invest in cordless impact if ya don’t have already). You’re gonna rip it all apart anyways and now will be easier to load and unload. And if its a junker, just keep the credit for the next one, or other stuff. Doesn’t hurt to just ask.

another thing is have a note with rare parts to look for everytime you go. The rare crossover, perfect condition thermostat housing, 9 blade metal fan, the unicorn db0 ip or any high desired ip (about 6-8 of them iirc).
 
I'm almost wondering if maybe saving my pennies and then reach out to you guys here in the forums looking for one would be a better option? your absolutely right on cracking, and being my luck every one I find in the junkyard will be that way. I remember back in the day working as a auto mechanic (when I was young n dumb) our shop owner had one time ordered a reman engine, don't remember if gas or diesel, from one of the auto parts stores and kept returning it before it came out of the crate 5 or 6 time until he got one worth installing!
 
I seen that one outfit that has diesel components and remanned enjuns also has the Optimizer engine blocks for sale. I dont remember the name of the company or how much they wanted, but, it popped up in one of the threads here within the last week or so.
 
hey Guys, today I was just doing a once over on the truck, something was telling me to look! lol and I did. saw the most obvious was the oil cooler rubber hoses were wet with oil. ran down to Napa grabbed some 1/2" oil hose and a hand full of clamps and went to town. cut off the crimps with a drimel toom and on with the new hose. double clamped on each end.

later on I got to playing with the boost solenoid, had seen a video on youtube on how to clean it. since I get a code set every time I go over 70, I tried my hand at cleaning it. that went well. reinstalled and then decided to connect the laptop with GMTD to test. here is where things get interesting!

I need an opinion or advice on this....

using GMTDscan the solenoid would not respond at all. all it would do was allow full vacuum to the wastegate. while the engine was idling I pulled the electric connector and poof the wastegate no longer had vacuum! reconnected and full vacuum. I sat there scratching my head... the solenoid must be working since it aparently has to be connected for it to pass vacuum to the actuator. after pondering this for a bit, a curiosity hit me. what if I tried connecting the PCM that I pulled from the junkyard just to see what it does.

Well I did just that.. connected the salvage pcm, key on checked for codes, nothing, so I cranked her up. seemed to run fine, almost seemed to idle smoother. on GMTD I selected the wastegate control. checked for vacuum before hand and it had full vacuum. set the duty cycle to zero and clicked "SET". checked the actuator and it had no vacuum! tested several times on and off. the junkyard pcm was controlling the solenoid!

I ran a snapshot to compare TDC offset and other things. attached are both the snapshot from when I had did the relearn and set the TDC on my pcm, and the snapshot if this junkyard pcm.

questions...
1. can my pcm be failing
2. with the differences in the TDC and resistor numbers, can I leave this pcm in without doing any harm?
3. should I run the relearn to set the TDC and run it?

and feel free to tell me more good and bad :)
 

Attachments

I would like to play the IP position and get some better numbers, but I know my wife won't like me very well if I go jacking around with the truck more lol

I suppose it would be best to run the relearn for now and see if I get a code for the wastegate. I just seemed odd that my pcm wasn't able to control the solenoid and the junkyard one does. it's also making me think about my glow plug time only got 5 seconds even with the ECT disconnected. I had installed a digital timer relay I got off amazon and set it to 8 seconds for every key on. that has fixed my struggling startup's I was getting. I would have to disconnect the relay and hook it back to normal to see if anything is different on this pcm. it's just got me scratching my head wondering if my pcm is dead or has malfunctioned in some way.

I don't know how the programming in the chip works and thought that mine just has a bad flash from factory. as much as I work with computers, this would be something I would love to learn. I know OBD1 is a thing of the past but old hardware and software has always interested me. the thought of being able to read the parameters on my chip would have me at a WOW factor! lol
 
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