Front mounted coolant overflow?

[Beerj]

Anyone ever mounted one up front on a rig with a rear mounted radiator? Idling level or facing downhill mine does fine. However, facing uphill at idle, the temps climb. Raising the rpm's brings the temp back down but I'm not 100% sure yet if that trend will stay of if it will eventually stop cooling down and start heating up again over time. Additionally, I'm not sure what will happen giving it a workout facing uphill.

Logic tells me it must be building steam and is unable to burp when the radiator is the lowest point however, I haven't noticed any burping after returning to level or nose down.

This got me wondering if running the steam vent line into a catch can up near the engine would prevent any steam pockets from clogging up the coolant hose. Thoughts?

 

[Beerj]

Another interesting find to note. The radiator is completely full and stays that way at idle. But as soon as throttle is applied, the level in the radiator drops a few inches. Makes me think there's some cavitation going on somewhere.

 

[Jduck]

What engine?

 

[Beerj]

Lq4
Being it's a truck engine, the water pump outlet comes out the top. I had to use a 180° fitting to go back down to the chassis. That is all below the radiator but it's the highest among the rest of the engine and even 99% of the path that the coolant travels. I'm thinking that maybe adding a bleeder to the top of the fitting couldn't hurt.

 

[Jduck]

Where's your steam port plumbed into?

 

[Beerj]

It was originally plumbed to the passenger side chassis tube. In hindsight I'm surprised it worked for as long as it did since it was basically just sending steam back into the engine. Now I have a dedicated line ran back to the radiator. I tapped in below the pressure cap so the system would stay pressurized.

 

[Dirt700]

I tapped my water pump this weekend for my steamport, I have a cheap eBay overflow tank mounted to rad. Does the overflow tank need to be sealed? It has 2 fittings on the bottom. One I ran from radiator neck, the other is if the tank gets too full

 

[Dirt700]

https://m.ebay.com/itm/3-X-10-Polished-Stainless-Steel-32-OZ-Radiator-Coolant-Over-Flow-Puke-Tank-Can/202299548768?hash=item2f19fe2460:g:Ie0AAOSw43Ba4o-J

 

[Beerj]

I have that exact same overflow at my radiator. Typically, the port that would feed the overflow is above the sealing ring on the radiator cap. That way you can keep pressure in your cooling system and if too much builds, the cap allows the excess to go to the overflow. If you just had, for example, steam ports or a vent tapped from the water pump ran to the overflow, then your cooling system would never hold pressure. Pressure is important since it raises the temperature that your coolant will boil by 2-3 degrees for every pound of pressure. So if you run a 15 psi cap, your coolant shouldn't start to boil until at least 252° since you gain some boil protection just by having a 50/50 mix of coolant.

 

[yankster]

After doing some reading I changed to a CTS-V water pump when mine was doing the same thing. Apparently the flow rate is higher at idle than a truck pump.

 

[Beerj]

I've definitely been considering a pump swap. I was really liking the electric pumps just due to the fact that I could continue cooling things down with the engine shut off. Though I think mechanical pumps flow better at high rpm's.

 

[Beerj]

That makes me feel better. I already ordered an aluminum weld on -4 fitting that I'm just going to weld on the highest point of the u-turn and cap it. Should accomplish the same thing.

 

[Beerj]

Thanks for the input man. I think we're on the same page. There are 2 other spots on the chassis that were suspect so I got 2 steel fittings to bleed those spots as well. Thinking back to when I originally got it going, I had issues early on with the temp climbing at idle but dropped with throttle. That eventually worked itself out, probably from just getting into some good angles to burp that last bubble. Getting a bleeder above the water pump exit I think is going to be the key. Especially like you said, crack it every once in a while just to keep the air out.

 

[Dirt700]

I have the same engine, same pump and I "used" to have the same problem. The outlet on the pump going up then looped back down is your problem. It traps air at the high point. All you need is a jegs inline hose drain, facing up. Bleed it initially and check it once before each trip and you'll be fine from now on. I tapped an additional port into the hose drain to run my steam port to it.

https://www.jegs.com/p/JEGS/JEGS-Inline-Radiator-Hose-Drain/1206363/10002/-1

Do you have braided hose, or just rubber? If I end up with this problem I may give it a try. I'm using -16 hose

 

[Beerj]

Well I think I've done all I can realistically do at this point. After running the steam port back to the rad and adding a bleeder above the water pump outlet, I decided to try it without a thermostat since there was mixed reviews on if it cools better. In my case, no. At idle it was excellent, held around 155°. Throttling up it would drop to about 145° but then climb until I let off. I never let it get above 230°.

After some more research it seems that at least these water pumps work better with some restriction. Lack-of can apparently cause cavitation which reduces flow considerably. I suppose that's why some guys just run restrictor washers. So today I threw in the original 180° thermostat that I had in. I gotta say, having that bleeder above the pump made getting the air out a breeze. No huge burps that spit out a half gallon of coolant on their way out. She now idles consistently between 177.8° and 179.6°, all the time, to nearly the exact same decimal. Throttling up, it drops as low as 168° and never climbs above 170° until I let off.

So in conclusion, I'd say things are looking good although it's hard to say if rerouting the steam port or adding the bleeder is the hero. Either way, I'd strongly reccomend the bleeder for at least the benefit of being able to evacuate any air pockets that may develop. At this point there really isn't anything to do except load it on the trailer and hope she stays cool at Harlan next month.

 

[Beerj]

I see. I was originally excited about the idea when I could look in the rad at idle and see tons of flow. But I suppose at any throttle rate it's enough to recirculate in the engine like you said. I'm still wondering if there would be a benefit to running a line from the bleeder, back to the radiator. I am worried though that it would just be an opportunity to allow air from the rad to enter at the bleeder rather than evacuate when on an incline. Physics tells me air bubbles go up and will always look for the highest point.

 

[Dirt700]

I'm thinking now, where I have my pump tapped for steam line, putting a tee in and putting a Barb on the side for steam line. Then using top to run up as a bleeder

 

[Beerj]

I'm thinking now, where I have my pump tapped for steam line, putting a tee in and putting a Barb on the side for steam line. Then using top to run up as a bleeder

I just lookerd through your build thread and didn't see any mention of how you're running the pump outlet. If the outlet never gets above the steam ports then that idea should work. However, if it's like mine and Waffles, it loops up higher than anything else on the engine and will collect air there. Being able to bleed the pump would still be helpful but it may not get all of the air out if there's higher points.

 

[Dirt700]

Re: Re: Front mounted coolant overflow?

I just lookerd through your build thread and didn't see any mention of how you're running the pump outlet. If the outlet never gets above the steam ports then that idea should work. However, if it's like mine and Waffles, it loops up higher than anything else on the engine and will collect air there. Being able to bleed the pump would still be helpful but it may not get all of the air out if there's higher points.

I will take a picture tonight. I have a -16 fitting sticking up, my hose 90s off of that over to driver side frame rail

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[Dirt700]

The bleeder would be higher than my outlet

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