Coolant bypass hoses

[Onefaststang]

I came across a thread where a few have been drilling into the heads and adding external coolant lines. Then a came across one stating this was a bad idea. Was there ever any concrete evidence that t this is a good our bad idea? My heads are off right now and am considering it.

[Powerhead357mag]

When I had my lightning I did it on the back of the heads. But I'm not sure if these trucks have the "dead spot" of coolant flow in the back of the heads or not. I'm sure others will chime in.

Tim

[Term3]

There are several big name diesel performance shops that recommend doing this to get coolant going thru the hot spots at the back of the heads. Only good things can come from doing this. You drill and tap into the back of the heads. Then you do the same thing just below the thermostat.

When I swap the front cover on my engine to put in the 100 mm water pump I'll be putting a brass spacer under the thermostat to tap into for that end (supply) of the coolant lines just because I feel better with more thread contact then the thin front cover material. Your not robbing coolant flow from the rest of the engine since it's coming off before the thermostat which is as we all know a restriction in the system.

[Onefaststang]

What size line comes with these systems? It looks like a -6 but I can't really tell from what I have seen. Curious if out would be sufficient to use-4?

[Term3]

I wouldn't go smaller then a 3/8" ID equivalent.

[toughluck13]

ive been woundering about every ones thoughts on this as well

[work&play]

I put them on my truck when the head studs were done.
They are only $150 and they can only be put in with the heads off.
I figured it can't hurt with the daily weight of my truck, 12,000 lbs.

[hogasm]

Run a garden hose out in your yard and attach a sprinkler to it....flows fine

Attach another length of hose to that sprinkler and another sprinkler at the end....first sprinkler flows better

Attach another 2 just like above.....first head-good next=less 3rd=less than 2nd head 4th head=sprinkler with a prostrate problem

Why do the same to your motor???

[Term3]

Originally Posted by hogasm

Run a garden hose out in your yard and attach a sprinkler to it....flows fine

Attach another length of hose to that sprinkler and another sprinkler at the end....first sprinkler flows better

Attach another 2 just like above.....first head-good next=less 3rd=less than 2nd head 4th head=sprinkler with a prostrate problem

Why do the same to your motor???

I understand your logic but it does not really apply fully with a closed system. For example if you have a long tank with a lot of baffles in it and a pump circulating in and out only at one end the liquid at the other end of the tank will take a long time to make it thru to the pump but if you take a small flow off that pump and pipe it to that other end of the tank the whole tank then gets circulated by the pump with no change in output volume of the pump. That is basically what these bypass lines are accomplishing.