| Author |
Message |
Mike M (66.159.146.54)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 10:28 am: | |
Should the water Flow thru radiator in at the top and out bottom, or the other way around?
My original thinking was heat rises so draw from bottom, but the pressure from the pump into top of radiator is forcing coolant out the bypass. (and its not even hot yet).
Time to re-plumb? or get a higher pressure cap?
Thanks,
Mike McCarthy
'69 GMC 4903 |
Marc Bourget (209.142.38.81)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 10:34 am: | |
Gosh, this depends so much on the individual design and installation of the coach. I dont' recall what coach you have, if you've been re-engined or???
The 8V92 was out of my coach when I got it.
typical auto installations intake from the bottom. I'm guessing that the hot from the engine is dropped to the supply side of the radiator as a step in de-aerating the coolant before it travels through the tubes. You have to look closely, some radiator installations put a baffle in the far side so the coolant makes two passes through the radiator core
It'd help to have more info.
Onward and Upward
Marc Bourget |
Mike M (66.159.146.54)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 11:07 am: | |
Remote radiator for generator. |
James Maxwell (Jmaxwell) (66.81.62.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 11:16 am: | |
If it is a vertical flow radiator, in @ top-out @ bottom. That puts the water level below the water pump at all times, providing you have a full level of coolant. The radiator acts as a resevoir for the pump to draw from. |
David Anderson (168.215.176.193)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 3:16 pm: | |
Logical engineering tells me to do like James stated. This way the bubbles are already at the top and the pump intake from the bottom is guaranteed 100% water without bubbles. No cavitation. Just my thinking.
David |
TWO DOGS (63.185.73.78)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 3:26 pm: | |
always "in" at top..wheather verticle or horiziontal flow... |
Mike M (204.60.218.249)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 7:07 pm: | |
Thanks, The way it is set up now, the pump is below the radiator, but draws from the engine and pumps into top of rad.
I think I'll re-plumb it to draw from bottom of radiator and pump into engine. |
BrianMCI96A3 (208.13.141.32)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 8:12 pm: | |
Mike, what pressure is the radiator cap?
Brian |
Sojourner (68.60.169.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 15, 2004 - 11:24 pm: | |
By-pass is to by pass thermostat to have circulating within engine to get hot coolant to reach thermostat's bulb to open.
Which mean a by pass hose is connected between pump and before or under thermostat unit.
All radiators are design with top as inlet and bottom is outlet connect to engine’s pump then to engine’s bottom water-jacket.
Why it important? Because cooled coolant is heavier & shrink then hot coolant which is lighter & expanded.
So it circulates easier.
In early days, thermo-siphon was only way to circulates. Then radiator has be vertically center or higher in relation to engine, otherwise poor circulating.
Now since about WW 1, water pump was added to improve circulation.
With the help of water pump we now can use cross-flow radiator instead of vertical-flow radiator.
Which mean remote overflow tank is added to eliminate air in coolant system and as well for convenient location.
Otherwise, air pocket before thermostat while engine running normal or higher temperature will not open until hot water contact thermo-bulb.
Some cases a remote expansion tank needs to better access pressure cap to fill plus overflow tank to keep cooling system air-free-filled.
Hope this help to solve the wondering mind.
Link;
http://www.arrowheadradiator.com/diesel_truck_cooling_system_solutions.htm
For what it worth.
Retired automotive diagnostician.
Sojourn for Christ, Jerry |
BrianMCI96A3 (208.13.141.32)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 16, 2004 - 8:45 am: | |
If I'm not mistaken, the baypassing Mike was talking about was coming out the radiator cap. If that was the case, I think checking the cap for holding rated pressure is in order, and depending on the pressure it holds perhaps a higher rated cap is in store.
Brian |
DrivingMissLazy (66.168.175.51)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 16, 2004 - 11:27 am: | |
Jerry, you sure do come up with some great information. Thanks very much.
Richard |
Sojourner (68.60.169.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 16, 2004 - 2:54 pm: | |
Thank you DML.
Brain......It could be??? “About was coming out the radiator cap” there a two way valve in “over-flow” cap. Outlet is pressure regulate but open freely inward via vacuum to draw coolant.
However without prior owner’s bus history in regard cooling, it makes it harder to pin-point problem.
So, by going thru the route of explaining the purpose of all its function such as cooling system that I have already posted.
Then it may help themselves to find it own problem or problems.
Nothing better to help diagnoses problem then being there to ask whatever history, look and troubleshoot the problem.
After doing diagnostic for many years, you will learn the common problem of each brand or make.
A history about engineer’s goof in productions (rarely but does happen);
1) Nash Rambler in 50’s came out without by-pass circulating system…so they over heating and blow head gasket. Later it came with by-pass.
2) Brand new 1967-68 Buick came with cross flow radiator without overflow tank.
Work at 1967-69 largest Buick dealer in world, Jerry Davidson Buick in Flint, MI. (20 to 85 new cars per day) as dynamometer operator and diagnostician.
Practically every one of them have had 3 or more head gasket replace until Buick Motor Co. add a overflow tanks to customer’s cars. Because having air in radiator’s tank will cause higher rev water pump to suck air while kick-down throttle (engine rev-up) to pass cars, to create air pocket under thermostat’s bulb to close until hot liquid touch.
Remember air pocket temperature (under thermostat) too cool to open until hot enough to reach thermostat setting.
Most all thermostat are equip with bleeder but not fast enough while driving, so be sure whenever re-service cooling system you bleed all air out.
For what it worth.
Retired automotive diagnostician.
Sojourn for Christ, Jerry |
BrianMCI96A3 (208.13.141.32)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 16, 2004 - 11:43 pm: | |
So, anyway Mike... was the coolant coming out of the radiator cap, or what?
Brian |
Mike M. (64.252.215.39)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 8:15 pm: | |
Yes, and the cap was 8psi. I tried the cap off my 79 bronco (12psi I think)and had same results.
Do they make higher pressure caps? |
BrianMCI96A3 (67.76.66.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 10:33 pm: | |
Yes, they do, though 15 psi or 16 psi might be the highest pressure cap I'd try.
As long as your radiator is in good shape it will handle that pressure easily.
Mike, when you say that there is coolant coming out of the cap how long does it take before it begins to spit out of the cap?
I know it is before the engine heats up, but is it a matter of seconds?
As a diesel mechanic with a quarter century of experience if it is a matter of seconds, my next step would be to run the engine without the radiator cap in place.
If shortly after start-up you begin to see large bubbles appearing out of the coolant...I would begin to suspect exhaust gas in the coolant...
I sure hope that isn't what you see.
Brian |
Sojourner (68.60.169.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 18, 2004 - 12:23 am: | |
There you have it Mike, like what Brian said, run your engine fast idle with cap off to see if bubbling or blowing water out would indicate leaky combustion gas into coolant.
However be sure every coolant passage is purge before above test.
I have use “Block check” to check for combustion leak many times in the pass.
A time saver to say the least.
While engine fast idle @ cold and @ normal operating temp, insert “Block Check” on top of radiator filler neck and squeeze BC bulb to draw air or gases. Then BC blue liquid will turn into yellow or clear color if has combustion leak.
Some radiator shops have them to check customer’s cooling system.
NAPA sells them for fleet users;
http://www.napaonline.com/cgi-bin/ncommerce3/ExecMacro/NAPAonline/search_results_product_detail.d2w/report?prrfnbr=15616548&prmenbr=5806&usrcommgrpid=
It good that Brian ask the question to Mike to narrow down the problem.
Be sure all hoses are routed properly and hook-up to proper tap.
Like Brian said, get a 2 cycle V6 engine mechanic to check it out.
Wish you well.
Sojourn for Christ, Jerry |
BrianMCI98A3 (67.76.66.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 18, 2004 - 11:58 am: | |
Actually Jerry, I didn't say that.
And I'm fairly certain that Mike's gen. isn't powered by a two stroke Detroit.
But, If Mike DOES observe exhaust gas bubbling up in the coolant, it might be time for a mechanic's opinion in person.
Of course, if there are large bubbles in the coolant Mike could spend $50 or so for a Block Check to confirm that is exhaust gas, first...
But then, if he takes the engine to a mechanic with a complaint of possible exhaust gas in the coolant, the mechanic will more than likely do a Block Check himself.
Brian |
Sojourner (68.60.169.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 18, 2004 - 8:52 pm: | |
I am sorry Brian, I apologize for misquote.
I didn't read subject "Gen" before message so it not likely 2 cycle diesel. Again I am sorry.
And I was not trying to impose anyone to buy "Block Check" but only to tell about it.
Thank you Brian, for clarified this post.
Sojourn for Christ, Jerry |
BrianMCI96A3 (67.76.66.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 19, 2004 - 1:06 am: | |
Not a problem Jerry, we all are just trying to be helpful
Brian |
BrianMCI96A3 (67.76.66.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 19, 2004 - 8:15 pm: | |
So Mike, any updates on the situation?
Brian |