2.5.4, MPG Mike #4 coolant mod - cancled

[Murphy]

This is the #4 coolant mod done by MPG Mike. It connects the bleed on the thermostat housing to the freeze plug on the side of the head. It works well and my plug in the 4th cylinder looks darker(richer) than the rest of the cylinders. The only disadvantage of doing the coolant mod this way, is it makes it harder to get to the #4 cylinder spark plug

[glhs875]

Looks good. That's similar to the way I'm going to do mine except I will be using the lower port on the themo housing. My turbo isn't water cooled. I have to make some changes/upgrades since I blew out a chunk of the head gasket @ around 30psi on cylinder #4.

[GLHS592]

The only disadvantage of doing the coolant mod this way, is it makes it harder to get to the #4 cylinder spark plug

You could make your hose longer so that it is in front of the access hole. I think I will do this soon. What size fittings did you use? 3/8 NPT?

[Frank]

Not sure if I am going to add this one. While it may work, the other method is preferred and recommended the most by TM.
http://www.turbo-mopar.com/forums/kn...section2#2.5.4

Comments?

[glhs875]

Not sure if I am going to add this one. While it may work, the other method is preferred and recommended the most by TM.
http://www.turbo-mopar.com/forums/kn...section2#2.5.4

Comments?

Couldn't the freeze plug area be used instead of drilling and tapping the head?

[Frank]

I meant routing it to before the thermostat. It is better with fresh coolant from the pump.

[glhs875]

I meant routing it to before the thermostat. It is better with fresh coolant from the pump.

I agree. Stock, by the time the coolant makes it to #4, it's already heated up big time from cylinders 1-2 &3.

[johnl]

Look at this thread - http://www.turbo-mopar.com/forums/sh...hlight=coolant

Based on Rich Bryant's findings, when the engine is still cool and before the T Stat opens, this set up means that flow is going from #4 and through the T Stat housing and then out through the heater by-pass pipe and thence on into radiator tank (early pumps/L Body) or the low side of the water pump housing (later/whatever).

All the methods works though.

[The Pope]

I agree. Stock, by the time the coolant makes it to #4, it's already heated up big time from cylinders 1-2 &3.

flushing the water through the head faster will make the whole head work better. Purposely making one cylinder cooler is a band aid. I am doing a flush with a 5/8" hose from the freeze plug to a water / oil cooler and then into an early G body water pump housing. Your still pressurizing the engine for coolent but flushing nearly 40% more coolent through it. So you don't have hot spots and a more equalized temp through the engine. Porting and polishing the water pump housing changes drivabilty for the better. Super easy and cheap mod if you want better cooling.

As for this mod directly, I don't think it will work. The reason is pressure creates flow. There is equal pressure there and your trying to run it up high where air gathers in these heads from slow flow. The way I described it you are creating a vac where you need heat removed. The origanal method is under higher pressure and forces more coolent up there. So I don't see how your going to move the coolent. Another idea it to step to a larger pipe at the freeze plug, from the turbo. The coolent from the turbo is pressured higher and will pull the coolent as it goes by. How do I know? I build hot tubs and that is basically a jet! So you would get flow the same way you get bubbles on a vac style hot tub

[rbryant]

Look at this thread - http://www.turbo-mopar.com/forums/sh...hlight=coolant

Based on Rich Bryant's findings, when the engine is still cool and before the T Stat opens, this set up means that flow is going from #4 and through the T Stat housing and then out through the heater by-pass pipe and thence on into radiator tank (early pumps/L Body) or the low side of the water pump housing (later/whatever).

All the methods works though.

The only thing that I would add to that is that you really should have coolant leave from both the waterbox and the #4 freeze plug for this mod.

The reason is because you can get some stagnation inside of the waterbox if there isn't constantly coolant flowing by the thermostat. That is why the VW engine has coolant leaving from both places. This is easy to accomplish with a tee in the line that goes to the heater core. My setup is working fine but I have see the temperature gauge move a little bit more drastically than I would like on initial warmup. This makes me think there is some stagnation there since my temp sender is also in the waterbox.

This method will work but I think that it is less optimal when the stat is closed because I think almost all of the coolant will leave via the waterbox rather than the #4 line because it is a much less restrictive path (bigger hole and less of the head to travel through) and will still starve the #4 slightly.

-Rich

[mpgmike]

Being the head porter that I am, I was looking for a way to improve the situation having access to only the head. Perhaps this isn't the absolute best solution, but is an improvement that I could incorporate without having the vehicle at my disposal. If there is somebody that feels that it is worthless as an improvement, I'm all ears. If anybody has a suggestion how I could do it better having access to only the head, I'm all ears again. Thanks for the well thought out discussion.

Mike

[Frank]

I see the reasoning behind your method now, but I still have my doubts about effectiveness. However the only other solution I can see to meet your dilemma is to put a fitting on the billet t-Stat housing and run a smaller line between this fitting at the drill point on the head.

Definently a tough pickle!!! Thanks for the insight on your reasoning!

[rbryant]

Being the head porter that I am, I was looking for a way to improve the situation having access to only the head. Perhaps this isn't the absolute best solution, but is an improvement that I could incorporate without having the vehicle at my disposal. If there is somebody that feels that it is worthless as an improvement, I'm all ears. If anybody has a suggestion how I could do it better having access to only the head, I'm all ears again. Thanks for the well thought out discussion.

Mike

Your solution should work just fine.

-Rich

[johnl]

I see the reasoning behind your method now, but I still have my doubts about effectiveness. However the only other solution I can see to meet your dilemma is to put a fitting on the billet t-Stat housing and run a smaller line between this fitting at the drill point on the head.

Definently a tough pickle!!! Thanks for the insight on your reasoning!

Good one, Frank. A few days ago, I sent an email to TU saying, "make the flange thicker and drill, thread, and stick a barb in the flange to connect to #4." Thought I'd keep the idea on the QT. Then you spill the beans - and Frank(s). Now, that, for me, would be a really good reason to buy a billet T-stat hose fitting.

The flow would likely be more than adequate because, while it would be through a smaller ID/higher resistance hose than the heater by-pass, it would be a shorter/more direct route to the large ID T-stat radiator hose.

MPG Mike - No criticism intended, just analysing, and I get your point. My set up from the high side of the water pump troubles me because it is injecting colder water that has not been preheated by the block directly into the area around/above the #4 combustion chamber. The heat differential, under some scenarios, could be too great. I try to take comfort in the low volume flow (I hope) of about 3 feet of 3/8 ID hose.

[rbryant]

The flow would likely be more than adequate because, while it would be through a smaller ID/higher resistance hose than the heater by-pass, it would be a shorter/more direct route to the large ID T-stat radiator hose.

The real reason that it gets less flow is because the waterpump is now sucking water from the main waterbox port on the heater bypass only when the stat is closed. The vast majority of the water will come from the 1/2/3 cylindars rather than the #4 bypass because of the size of it.

If you have the same sized hose coming from both the #4 and the waterbox directly it will result in roughly half flow from both areas (assuming the pressure differential is roughly the same in both). With the line to the top of the waterbox the flow from the #4 will likely stagnate because there is a rush of water comming directly through the waterbox through a larger hole which is also likely at a higher pressure (combined flow from 1/2/3 rather than the extra restriction to get across the block to #4). the path of least resistance is for coolant to go from the 1/2/3 rather than from the #4 hose.

With all of that said it is still better than stock and probably just fine.

-Rich