As title states, anyone thought or have performed a modification of this sort? To help circulate coolant from left to right side of rear heads. Or any opinions as well.

 

Anyone? No one? Bueller?

 

When I was wondering if I had a cracked head, I thought about this for a short bit but since my failure was the block, the thoughts came to an end.

It could be accomplished a couple ways, including tapping the outside of the head into the jacket but honestly I'm not sure that this mod would bring all that many benefits.

 

As said before, the main reason these crack and fail is due to poor casting. Coolant flow is important with a good radiator, water pump, thermostat, etc. You'd be better off upgrading the radiator or doing something different with the fans or grille to allow more air flow. If you put in a cross over pipe, it might cause more issues than fix.

 

You're right. No doubt that's the cause but if we can ease the burden on them, then great!

After all, the heads would never crack if you didn't ever run the engine. It is the heat cycling that fatigues the poorly cast metal so, it might be a reasonable course of action to minimize thermal shock. More even flow is a good thing in general to minimize shock but like you said, I expect that decreasing overall temps would work more effectively and your suggestions are probably the best way to do it. A thermostat alone won't help in the worst of scenarios, only when the radiator can handle the load, that said, a larger radiator is the single best solution, the next is flowing more air through it, be it grille mods, better fans (e-fans perhaps) etc.

It appears heat soak is a major concern with these vehicles right? A vented hood could help greatly, I did a little testing in that particular field with hood venting and IAT some years back in race cars. Vented hoods work well, so long as the vent is up towards the windshield in the low pressure zone and preferably near the headers where most heat is generated. Above 30mph, fans don't do much work, the airflow of the vehicle moving does (hence why some vehicles shut the e-fan off around 30mph), so if you're over-heating while driving, the answer is a bigger radiator, if it's while stopped, it's a better fan and cowl.

 

Would those on the forum be interested in doing some testing on under-hood temps and data logging? I'd be willing to do some work on this. My vehicle is in process of a LS swap though so I won't be able to to use mine to help but I'd be happy to get on board with a project if someone can provide a vehicle. I'm quite confident we could greatly reduce the issue of over-heating in these vehicles in a very cost effective manner.

 

Agreed to the above posts, as of now snorkel has drastically reduced IATs by 50* (in miami FL heat), a thicker(not by much) all aluminum Chevy radiator with cap and the meziere inline therm mod with a 170* stat, as well as the condensor fan permanently on when truck is on. No heater core, nor the triple bypass, nor throttle body heater, nor pressurized expansion tank. I’ll probably get some sass for over modifying the cooling system however, it is doing great efficiency wise. Only problem I have(which isn’t a problem) is longer warm up time and the ecu thinking the thermostat is defective. As far as the rear cross over pipe, I was thinking drilling and tapping the lower intake manifold in both sides with a hose as opposed to the head or block. Just as preventive rear head coolant leak for the freshly build 4.0 about to slide in.

 

Yea but if you don't live in a cold climate, the warm up time isn't such a huge drawback, when I lived in Montana and there was -20 below 0 mornings, it would be a full 30 minutes to bring many vehicles up to temp and often they'd never even come up to full temp depending on the vehicle, in which case, pretty major draw back but you're in Miama lol, far from that issue.

There is one inherent issue with what you've done though potentially, that is that engines thermal efficiency is better when the motor stays hot, thus why new motors run as hot as +210*F, they get better fuel mileage. Yours will be trying to maintain a significantly lower temp but since it might not be able to, it wouldn't matter. I'd be curious to see what your temps really are, hopefully they ride around 190 at least though and below 210.

I too think drilling the manifold would probably be the way to do it and forming a little loop. Still, I don't know if it'd really be worth the trouble.