Anyone think big mods on 6.5 contribute to cracked heads??

[Vandermax]

It is so addicting to add power to engines. Gas or diesel, I find that I want to mess with my truck top make it better and faster. But from all the old timers that have 6.5s that keep them all stock , and maintain them perfeck, and treat them right, it seems they put a ton of miles on them. I have a friend that has 8-10 6.5 trucks in his towing buisness, and he has well over 400,000 miles on a handfull of his trucks. He works them very hard he said, but he maintains them very well!! I think the only mods he did to them, is turbo-masters and gauges. I think I will leave mine stock{other than 4in exhaust, downpipe, k&n airfilter, and homemade ramair!!} and see if I can get over 400,000 on them!!

[AC Bingel]

I have to agree with you about adding power being addicting.

I have a 1999 Suburban with 123,000 miles. Last month I discovered the block was cracked. About a year ago I started making some modifications. I read a lot of posts on this site for advice prior to making these mods. I started with a larger exhaust then added the gauges and finally a Westers ECM. I take very good care of my truck and don't abuse it. I can't say for sure the modifications caused the block to crack but it sure makes me wonder.

I was looking for a little extra HP for towing. If you are looking to get a few hundred thousand miles out of your truck and don't really need the extra performance, I would leave it stock.

[DA BIG ONE]

Cracked heads on 6.5td happen for many reasons w/o mods so adding mods w/o consideration and monitoring the beast is asking for trouble.

The 2 enemies of these motors are high EGT's and IAT's IMHO, and it all can be traced to the turbo turbine exhaust outlet being too small therefor contributing to "SUPERHEATING" air charge, exhaust manifolds, & heads.

Engine cooling mods are required on the older units.

The jury is still out on exhaust downpipe size of 3" because of limited CFM flow of the diesel @ the rpm's it operates w/say a GM-8 turbo, but add boost and I'm thinking 4" is required here, but how do we go 4" dia. when area is so tight?

[Bnave95]

EGT's and IAT's IMHO

This is what can happen even with a stock Eng. Just ask RJ. With out gauges you have no ideal where the temps are at.

[ronniejoe]

Actually, ECT is more a driver than IAT. The primary reason that heads crack is EGT. The mods that produce more power actually reduce the likelihood of head cracking by reducing EGT.

[DA BIG ONE]

Actually, ECT is more a driver than IAT. The primary reason that heads crack is EGT. The mods that produce more power actually reduce the likelihood of head cracking by reducing EGT.

I'm thinking EVANS waterless coolant for my diesel, your thoughts.
Thanks

[Bnave95]

I'm thinking EVANS waterless coolant for my diesel, your thoughts.
Thanks
Is this a additive or Replaces the coolent?

[DmaxMaverick]

Evans is a replacement coolant. It is used straight, without water. It has a boiling point well above 300

[DA BIG ONE]

[QUOTE=DmaxMaverick]Evans is a replacement coolant. It is used straight, without water. It has a boiling point well above 300

[Kennedy]

Waterless coolant is a neat product. I use it in my ATV's where mud filled radiators can cause overheating and boil over and boil over leaves us w/o coolant. It is less efficient as a heat transfer media, but will not micro boil.

IMHO Dex Cool/water is the best choice for the 6.5.

[Vandermax]

I do not have any gauges, and I tow about 10,000 pounds with my 98 burb, and I have not ssen the temps go above 220. It might look like its headed for 217 or so, and then the fan kicks on and she cools down to 195 pretty quick. Are these dangerous egts at like 240 or higher?????

[ronniejoe]

You really need to install an EGT gage. If you run at high engine rpm while towing heavy (up hill, for example), you are probably running over 1500F EGT.

Read the Part I article in my signature for more information.

[Kennedy]

Some may argue to disprove me, but engines with the high capacity cooling mods were far and awaty less prone tocracking heads while those without (even on "soccer mom" duty almost certainly cracked or lost a head gasket.

My '96 was run plenty warm prior to development of my fan clutch, and never cracked a head or showed signs of a head gasket getting ready (pitting of block) to fail. The key I believe is not so much how hot they get, it's uniformity of temps and consistency of coolant flow (no stagnation) up to the point where they boil and start to get into REAL trouble.