Should I modify the venting for my radiator?

[belfert]

On the Dina coaches, the radiator is mounted parallel to the rear engine hatch on the left side of the engine.  The radiator is mounted about 6 to 9 inches in front of the rear engine hatch.  Cooling air comes in from the left side of the bus through a vented door.  Dina created a metal tunnel to funnel air to the charge air cooler and radiator.

The back of the bus has no louvers for hot air to escape.  All of the heat from the radiator has to go down through that 6 to 9 inches of space between the radiator and engine hatch.

Would it make sense to cut a hole in the engine hatch and put in louvers or mesh or some sort to let heat out, or should I trust that the Dina engineers kew what they were doing?

My engine kept overheating on my trip home, but I also found when I got home that the air intake was plugged, the charge air cooler had some holes in it, and the exhaust pipe was cracked in half.  This has all been fixed.

I just don't want to get to the Rockies and have the engine constantly overheating again.  I don't have many hills to test on in Minnesota.

Brian Elfert

[belfert]

Anyone?

[TomC]

Can't hurt-can only help.  Good Luck, TomC

[Burgermeister]

Brian,

Tried posting this yesterday but it didn't take, I guess???

If you have access to a magnahelic guage,  I'd plumb the tubing before and after to see if the pressure behind the radiator was higher than before.

If it is, you've some work to do.  If not, leave well enough alone

Marc Bourget

[belfert]

Brian,

Tried posting this yesterday but it didn't take, I guess???

If you have access to a magnahelic guage,  I'd plumb the tubing before and after to see if the pressure behind the radiator was higher than before.

What exactly is being tested here?  Airflow?  I don't understand what you are trying to say.

I don't have any clue what a magnahelic gauge is, but I can do a Google search for that.

Brian Elfert

[RJ]

Brian -  Some photos would be helpful - it's kind of hard to picture what you're describing in your question.

[Burgermeister]

Brian,

A magnahelic guage is a senstive analog pressue guage.  An air conditioning contractor will know about them.

Mine has two tubes.  Place one open ended tube in the space before the radiator and the other behind.  if pressures are equal the needle is in the center. 

If the pressure is higher behind the radiator, it's telling you that the outlet is restricted.

You could do the same thing with a length of clear tubing and colored water.   Loop the colored water by taping it to the outside of the bus on top of some white paper.  One open end before the rad and the other aft.  the water will be even at rest.  When you drive the higher pressure will be the lower side of the water.  Run it down the road and have someone follow along side.

Marc Bourget

[DrivingMissLazy]

Marc, what would be a realistic number for the amount of restriction that a normal radiator would offer, as compared to one that is partially restricted.

Richard

Brian,

A magnahelic guage is a senstive analog pressue guage.  An air conditioning contractor will know about them.

Mine has two tubes.  Place one open ended tube in the space before the radiator and the other behind.  if pressures are equal the needle is in the center. 

If the pressure is higher behind the radiator, it's telling you that the outlet is restricted.

You could do the same thing with a length of clear tubing and colored water.   Loop the colored water by taping it to the outside of the bus on top of some white paper.  One open end before the rad and the other aft.  the water will be even at rest.  When you drive the higher pressure will be the lower side of the water.  Run it down the road and have someone follow along side.

Marc Bourget

[tekebird]

Brain don't spend your time or $$ fixing stuff that you don't know is broke.

[tekebird]

you might want to be concerned that your bus is thinking your taking it back to mexico......might act up just for that reason...LOL

[belfert]

Brain don't spend your time or $$ fixing stuff that you don't know is broke.

Something was certainly broke on my drive home.  I had to baby the thing through the hills/mountains of Pennsylvania to keep it from overheating. 

I'm not sure if the repairs done have fixed it or not.  Nothing was done to the radiator or cooling system except I replaced the coolant.

Brian Elfert

[Burgermeister]

Brian,  After replacing the coolant, did you "burp" it to get as much air out of the engine as possible?

Richard,

Brian was asking about the exhaust outlet to the rear of the radiator restricting the flow through the radiator. Like trying to breath out of a straw when you're exercising.

I was suggesting he see what the pressure was, downstream of the fan and before the 9" exhaust slot.  Anything greater than ambient would reduce cooling capacity.

The manometer or magnahelic would tell you if the pressure past the radiator is higher than the pressure before, (i.e. ambient).  I would take this as an indication that the outlet is restricted.

Are you asking about the restriction of the air flowing through the radiator?  That's a "depends" type of thing, greatly dependent on the number of fins, type of fin design, rows of coolant tubes, etc.

For the most part, the more air and the faster it travels through the radiator, the better cooling you'll obtain.

The figure you have to worry about when restricting the radiator is the pressure drop past the core and before the fan.  It would depend on tip speed because the concern is making sure the fan tips don't go supersonic.  They can if the pressure drops too much because the speed of sound drops with pressure.  So this aspect is a "depends" thing.  Best to keep the outside clean as possible.

Marc

Marc Bourget