Build Lexus LX450 Cummins 6bt/NV4500 swap

[warezdog]

It's a possibility, hottest egt has been 980f for only a few seconds. This engine is not being pushed one bit, it should have no issues holding 2x the boost and 300f hotter EGT and 9 deg more timing.

I have very little intrested in tearing this thing down, to the point I would likley not and just sell the truck.

I say go with a 50/50 mix run and recheck it, not saying the engine is being pushed at all and we all know it can do way more.
That near 100% water mix is prone to steaming pretty dam quick in the head even during normal egt's and with rapid expansion it has to go somewhere, the fact that it's coming out of all 6 tells me it's just water boiling off into steam looking for the easiest escape route.

 

[Wheelingnoob]

Well today I finished the cooling system flush, still need to get a coolant filter on but it's now got 50/50 water coolant. Plan to flush it out again when I collect the coolant filter stuff.

Ran the truck for 25min to burp the system and elvated the front end 3ft to assist in bleeding. System temp got to 145f and stopped there I can't get it any hotter with out load. The rad hoses where firm so there was pressure in the system, I did not see any water leaks at all yet. Not assuming it's fixed yet till i can get on the road but maybe a glimmer of hope.

I also washed the engine off in hopes a leak would be apparent.

Also drained the front diff (soupie) and put in new gear oil mixed with ATF to try and clean out the soup. I stopped the mixing of fluid and grease a while ago it's just very hard to get that s*** out once it's in. I'm hoping to detergent in the ATF losses it up and I can stop dealing with that crap. Likely drain and fill again in a few 100kms.

No time to drive the truck today or likley this weekend. I had a long weekend trip planed but removed myself from the group trip as there was understandably some concern's from all parties about the reliability of my truck and possibility is more issus.

 

[JuliosLX450]

Right on man.
You're better off not going on any roadtrips.
Just drive it around town during the week and if any issues pop up at least you're close to home. If all is well by the weekend go on a little adventure close by.
BTW it's very unlikely that the water mix was boiling and steaming out the bolts. ...if anythibg it would puke out of the radiator reservoir.

 

[Wheelingnoob]

Thanks Julio,

Here are a few pictures from yesterday.


Clean water markings.




Getting tired of pictures like this....



Post head stud retorque......bubbles between the HG and block/head. Only one bubble I think but none the less.



Just to clarify it's not leaking out the studs it's just and the seam of the head gasket and block/head.

Julio I have a company truck so this does jot get driven at all during the week and really do not have any free time to drive it with a 1 year old in the week anyways.

My wife and son leave for 10 days back east to visit family next weekend so I'll be able to put some good millage on I hope.

Agreed it's not a good idea to take this thing on any long distance runs for a bit.

 

[SeaDrifter]

Not sure it's been mention.. But maybe blocks been deck before? Maybe needs a 10 over HG?

 

[scottryana]

I am keeping my fingers crossed that by retorquing the head studs you have solved your problem. I think if you were able to squish out a bubble when you torqued everything back down it stands to reason that it wasn't quite clamped down all the way. Good luck man! We are all pulling for you. This would be a giant kick to the dick if something was wrong with this engine too.

 

[warezdog]

BTW it's very unlikely that the water mix was boiling and steaming out the bolts. ...if anythibg it would puke out of the radiator reservoir.

Not unless the thermostat is open otherwise there isn't anyplace else for it to go. The water jacket flow runs right underneath the ex mani, normal EGT would be sufficient to heat the mani and transfer a good amount of that to the head, enough so that it would boil a small amount of a mostly water mix in small enough quantities before the the Tstat would be warm enough to open up.

My bet is that this problem won't be a problem any longer with a retorq and a 50/50 mix

 

[Wheelingnoob]

Not unless the thermostat is open otherwise there isn't anyplace else for it to go. The water jacket flow runs right underneath the ex mani, normal EGT would be sufficient to heat the mani and transfer a good amount of that to the head, enough so that it would boil a small amount of a mostly water mix in small enough quantities before the the Tstat would be warm enough to open up.

My bet is that this problem won't be a problem any longer with a retorq and a 50/50 mix

Cool picture!

On the dodge variant of the 6bt there is a steam bleed that bypasses the t stat but your logic is sound. Well see how things go when I get a chance to drive it again. I have a buddy coming over tonight with a snap-on coolant pressure tester so we will pressurize the system and see if it leaks. Fingers crossed this is fixed.

 

[warezdog]

I think you'll be OK, at least if ANYONE deserves to be it's you!
A Cummins tstat won't open with just pressure as some might think, if it did then that flashing steam would have somewhere else to go rather than weeping from the gasket.

Now the question of your block being decked before hand brought up by @SeaDrifter was another good question, do you have the old head gasket to look at to see if that might also be a possibility? 10 thou could also be a culprit if the block had been decked prior.

 

[Dirty Koala]

The cummins thermostats open at either 180 or the 190, depending on which one you have installed. Since these motors run cool, it takes some effort to get them up to operating temp. With the water jacket running under the exhaust It's likely that your exhaust boiled a bit of water before the thermostat got a chance to open.

 

[Wheelingnoob]

I think you'll be OK, at least if ANYONE deserves to be it's you!
A Cummins tstat won't open with just pressure as some might think, if it did then that flashing steam would have somewhere else to go rather than weeping from the gasket.

Now the question of your block being decked before hand brought up by @SeaDrifter was another good question, do you have the old head gasket to look at to see if that might also be a possibility? 10 thou could also be a culprit if the block had been decked prior.

Yeah some good luck would be really welcome at this point.

I think the way the system is plumbed on the dodge it does have a bleed pipe from pre t stat to post. It's quite small though and has a jiggle valve in it.

The head had never been off this engine before I got it. Factory headgasket (stock thickness) sealed in with cummins factory paint. The guy I got it from was origonal owner and said all it ever had or needed was oil changes.

 

[Wheelingnoob]

The cummins thermostats open at either 180 or the 190, depending on which one you have installed. Since these motors run cool, it takes some effort to get them up to operating temp. With the water jacket running under the exhaust It's likely that your exhaust boiled a bit of water before the thermostat got a chance to open.

Not sure what one I have, I got it from cummins and they looked it up for a 96 dodge 6bt. I have not had the thing hot enough to even open the t stat yet so well see. It's starting to get warm here so well see if driving it now will allow it to open .

 

[Wheelingnoob]

I pressure tested the engine for 45min at 20psi and had zero pressure drop and no visable leaks. Looks like if it was leaking under cooling pressure this would have done it, the hoses where rock hard much harder than normal operation.

So fingers crossed it's no longer leaking. All head bolts are now set to 130ft/lbs.

I hope to have time this weekend to go on some long drives to see if the issue is fixed. Daytime temps should be in the mid to low 30c range and I would think that would allow the t stat to open.

 

[Dirty Koala]

Go haul arse up a few mountain passes, you'll be able to get the thermo open. Sounds promising, good luck.

 

[warezdog]

Forgive me for being a nag but you torq'em like this right?
I'm sure you did but I really want to see this succeed so I can copy down the road!

 

[Wheelingnoob]

Forgive me for being a nag but you torq'em like this right?
I'm sure you did but I really want to see this succeed so I can copy down the road!

Yep, I don't overlook stuff like that after all these issues lol.

 

[mistyv6]

bloock off half the rad with a bit of cardboard that will help it get warm

 

[IanB]

I hope to have time this weekend to go on some long drives to see if the issue is fixed. Daytime temps should be in the mid to low 30c range and I would think that would allow the t stat to open.

You seriously struggle to get the t-stat to open in the summer?!? Man, that thing will never throw heat in the winter, how do all the other Cummins do it? X2 on blocking off half the rad to help get the temps up.

Hope to hear your troubles are behind you soon..

 

[warezdog]

Fingers crossed for you Noob, and man that Holset looks so GD sexy in there!

 

[Wheelingnoob]

You seriously struggle to get the t-stat to open in the summer?!? Man, that thing will never throw heat in the winter, how do all the other Cummins do it? X2 on blocking off half the rad to help get the temps up.

Hope to hear your troubles are behind you soon..

Yeah last week when it was 16c on the hwy it was cruising along at 169f steady. I went up one steep ish hill and got up to 173f.

I can get heat out of the vents fairly quickly but it's slow to get up to full temp. I'm not complaining, after the isuzu always running hot it's a welcome change.