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Posted by: stecz May 4 2004, 10:43 PM

I've been having trouble with my '73 2.0 running hot... while I was under it I realized that one of the heat exchangers doesn't have the heater hose attached, so it just allows air to escape. I temporarily plugged the hole and low and behold it now doesn't run as hot (210 after 30 minutes of 80mph highway) and it cools down quickly when I slow down.


moral of the story... check the stinkin' obvious...

Posted by: Bruce Allert May 4 2004, 10:55 PM

It's fun to see wassup & under there, huh?

I like to put the teener on the ramps & lay under it. I just stare up at all the amazing stuff. I find a lot of things to either fix, upgrade or just monkey around with. These lil cars are so cool

.....b

Posted by: Rockaria May 5 2004, 08:13 AM

Maybe I am just slow, but how would a Heat Exchanger Heater hose help cooling? some air runs from the main pully fan through the shroud to the heat exchangers. Then out a hose to the heater flapper box. If the box is in the off position it just vents the hot air under the engine. If the Flapper is open it vents the hot air to the cockpit. Now, Air can also run from the electric fan through hoses into the top of the exchangers and out the other hose to the cockpit. If you plugged that hose on the bottom to the flapper, wouldn't it get really hot by trapping hot air in the exchangers?

Anyone?

Posted by: tat2dphreak May 5 2004, 08:23 AM

Posted by: ! May 5 2004, 08:59 AM

The fan moves air over the cylinders and oil cooler. The air assists the oil in cooling the engine and oil....

When a loose or disconnected heater hose allows air to escape the engine/oil temp goes up. Doesn't matter whether the heater is on or not. When connected the air is a closed circuit and works as designed. When a heater hose has a gross leak......the cooling air wants OUT....the effeciency of the air flow over the heads and oil cooler are disrupted.

When the heater is ON and the hoses are connected with no leaks, the flow is still regulated and the cooler and cylinders get their fair share of cooling. Plus the ambient temp is lower assuming that you use the heat when it's actually cold out.... <_<

Posted by: Rockaria May 5 2004, 09:07 AM

Posted by: Part Pricer May 5 2004, 09:20 AM

I'm with the slow guys here as well. Maybe we should get together and get a short yellow bus we can ride in together.

I've got HEs on my car, but no flapper boxes, heater hoses, nuthin. I have not had a problem with running too hot. And, I can't see how the heating path affects the engine cooling.

Posted by: Mark Henry May 5 2004, 09:30 AM

Posted by: Mark Henry May 5 2004, 09:34 AM

I've got HEs on my car, but no flapper boxes, heater hoses, nuthin. I have not had a problem with running too hot. And, I can't see how the heating path affects the engine cooling.

Posted by: tat2dphreak May 5 2004, 10:10 AM

Posted by: stecz May 5 2004, 10:39 AM

When the engine was running, air was exiting out the bottom side of the fan housing, through the heat exchanger and out the hole that should have had a hose attached.

My assumption is that the air was following the path of least resistance, so alot was exiting out the hole instead of through the oil cooler and over the heads.

As a by product, I think the heater is working better (the one side is hooked up)...

I was thinking about just disconnecting and going with headers since it worked so crummy, but I may have changed my mind.

Posted by: SirAndy May 5 2004, 10:56 AM

Posted by: McMark May 5 2004, 11:01 AM

If you don't have the flapper boxes/ hoses connected then remove the ducting that runs from the impeller fan housing to the HEs and plug those holes in the impeller housing with something. You have to get creative there, but they must be plugged.

Posted by: tat2dphreak May 5 2004, 11:31 AM

Posted by: Rockaria May 5 2004, 11:43 AM

Okay here goes... I always assumed the small ducting from the impeller fan hosing to the heat exchangers was to direct some air over the heat exchangers all of the time. Possibly to cool the exhaust pipes a bit, and to ad a little heat if the flapper box is opened a little. Then the electric fan came on when the flapper was full open giving lots of heat to the cockpit.

I assumed if you plugged that impeller fan housing path to the heat exchangers you would overheat the ehaust and exchangers becuase you stopped any circulation in the heat exchangers.

So what I am seeing is that you CAN plugg that hole stopping air from going from the impeller house to the heat exchangers and NOT hurt the exhaust system at all by overheating it.

Is this right?

Posted by: SirAndy May 5 2004, 12:08 PM

Posted by: stecz May 5 2004, 03:03 PM

most of the cars came with the Passanger side HE plugged from the factory!

Andy


???
So is there a plug that I can get that fits into the HE? Right now it's a total cluge. I was going to grind off the flange that looks like it should attach to the hose and rivet a piece of sheet metal there.

Posted by: Toast May 5 2004, 03:35 PM

Paul Heery,
I just wanted to tell you that your avitar is friggin Hillarious!
Been wanting to say that for a while now.
Thanks for the laugh.

Posted by: SirAndy May 5 2004, 03:41 PM

Posted by: Dave_Darling May 5 2004, 03:58 PM

Aaahndy, he's talking about the ones down underneath, at the bottom of the fan shroud. The engine cooling fan does indeed push air into the heat exchangers at all times. When the flapper valves are closed, this air (by now hot) gets dumped out underneath the engine. While it is not a ton of air, it is indeed some. Pull up on the heater lever, and stop just before the fan comes on. You'll find that some hot air does come out of the vents. Also, all 73-74 914s came with the passenger's side J-tube blocked (just where your illustration shows, but on the passenger's side). The pax can actually get some heat in those cars, which also shows that the engine cooling fan does move some air through the exchangers.

I doubt it's enough for its lack to cause overheating. But if you have no heat exchangers, it's a good idea to plug up the holes in the bottom of the fan shroud anyway.

--DD

Posted by: McMark May 5 2004, 04:05 PM

Hot air moves faster so having hot exhaust system is preferable. It will not damage your engine.

Posted by: SirAndy May 5 2004, 04:35 PM

Posted by: tat2dphreak May 5 2004, 04:54 PM

I think I have an extra Andy... pm or email me...