Engine Cooling Systems and Components

[Eric VanBuren]

In you pic of the 3 water pumps which is which? It looks like l to r gmb, reman oe, and airtex. The airtex is my preferred choice.

The fact that the temp climbs at idle and drops back down to the t-stats rating when you reach the "ram air" speed indicates that your fan is unable to move enough air through the radiator. That will likely cause a problem when crawling as the temp will continue to climb the longer you stay below 25mph.

Also if the factory "high temp" tvs used on a/c equipped rigs is still hooked and working, up in the oe manner, you will find that your idle speed will increase as the temp climbs and the vac advance is switched from ported to manifold vacuum. That system is there to increase the cooling by increasing the fan speed so that is a good thing. However running the 195 t-stat puts you closer to that point. I would be interested in what temp that occurs at, I swear I saw that at one point in one of my versions of the fsm. Of course that was when I was looking for other info and now that I want to find it I can't.

 

[Greg R]

Lou, you're really focused on this
I'm including a link with info from gould's pumps which shows some stuff right in line with what you're observing. The pictures are pretty graphic my paco pump manual has almost the same, but it's in the attic right now. Take note on figure 15-11.
How about the repair manual's procedure for disassembly where the shaft's snap ring in the bearing housing is removed and the shaft pushed out of the impeller to move the impeller farther out on the shaft? It might be less damaging than finessing with pullers, though I don't know what that would do to the seal at this point.

pump user's handbook: life extension - google books

 

[Lou]

Craig, how does one get the photos to display like you did them? Some of mine do and some don’t. I checked the FAQ’s but haven’t found any instruction.
The pumps from left to right are (1) factory re-man, (2) nos, (3) stamped or what I think is called airtex. The impeller on the table is an oem part. I think the airtex is about all you can find new anymore. I’ve read the factory manual and it states to press the impeller onto the shaft until the clearance is .015”. If it’s pressed to far the remedy is to ruin the impeller by removing it and pressing another. Having grown somewhat tired of this exercise I’ll go with the airtex steel blades and bend them gently to improve the clearance issue. The hub on my pump did not want to move. I left a decent dent in the end of shaft trying to pull it up. Also, the fan I installed is 17” as that’s all I could lay my hands on. I’ve got room for an 18” and will do some more reading on that. I will use either a steel flex fan or fixed fan with no clutch.
My ac is aftermarket from Arizona mobile air I installed it myself. I did note that idling in drive with the ac on puts the rpm at 500. I didn’t put it in neutral and up the rpm but I’ve only driven 10-15 miles so far. Over all the truck stays at the 195 thermostat point. I’ll keep an eye on it as I drive it more. I’m sure we’ve got some more 100 plus days coming and I’ll go out and idle on such a day.
Thanks for the comments and feedback, I’m still reading the linked stuff, good read.

 

[Lou]

I ordered an 18" derale fixed fan as the thickness of the new aluminum radiator won't let me use the fan clutch. That's fine as I intended on eliminating the clutch anyway. I'm looking at the sticker on the new fan (see photo) and I'm not convinced that it was placed on the correct face of the fan. The rotation is correct but there is a front and back to the fan that will have an impact on efficiency. The factory fan and photos I see on the net show the curved blade tips bent toward the radiator, this sticker would have them pointed away. I would also expect the cup of the curved blade to face the motor. Some other auto forums I visit have had a ball with this question when posted by others. Any thoughts here? Heaven forbid this be easy!!!

 

[Greg R]

You're absolutely right to question that sticker.
In my experience with prop fans, non-airfoil, the cup side of the fan faces the direction of flow. The oem engine fans also have the curved tips towards the radiator.
Think of it like shoveling dirt with the shovel the right way, then with the backside. Both ways move dirt, one way moves more.

 

[RobertC]

you're absolutely right to question that sticker.
In my experience with prop fans, non-airfoil, the cup side of the fan faces the direction of flow. The oem engine fans also have the curved tips towards the radiator.
Think of it like shoveling dirt with the shovel the right way, then with the backside. Both ways move dirt, one way moves more.

Huuhhhhh, then, what is wrong with the sticker?

It states "this side towards the engine" which means (to me, anyway) that the "curved tips" are towards the radiator...

Or, is my feeble brain twice confused????

 

[Lou]

The photo May be a little misleading. Here is a close up of that fan photo. With the sticker to the engine side the curved tip would point to the engine as well. Also, the cup of the blade would face the engine. The shove analogy is great; I have many years at the narrow end of an irish banjo.
I decided this morning that the sticker was on the wrong side and mounted the fan accordingly. This fan uses a 1/2" spacer so it's much easier to get my hands in front to run the bolts in. I've also got about 2" inches between the blades and radiator now.
I ran down some back roads this afternoon and did the Mike mayben power tune routine. I probably bumped the timing up 2-3 deg. Got home, it's in the 90's today and let the truck idling for 5-10 minutes and it sat at 197deg. When I re-start after several minutes it comes right back to 195 in about 20-30 seconds if I hold the rpm at about 1500-2000. All in all I'm pretty sure I've got this thing licked. The wife and I are headed to union valley to camp next weekend and I know of some nice 4-low roads to try. Life is good, thank you greg, Craig, Mike, Jeff and all who post here.

 

[RobertC]

Ok -- for some reason my brain thought the curve was the other direction in the first photo.

 

[Lou]

I sat here last night with two fans in my lap, checking the net for photos and shining my flashlight up into my whole house fan. I never thought I'd have to lable the moving parts of a fan so I could figure out what I was doing.

 

[Greg R]

The pictures seem confusing alright. I thought I saw the sticker on the convex side of the fan instead of the concave or cup side. But yet:

With the sticker to the engine side the curved tip would point to the engine as well. Also, the cup of the blade would face the engine.

In your last photo the fan appears Correct with the cup side facing the direction of flow towards the engine.
The curved tips have more to do with noise reduction than air flow, no matter. So you did turn the fan around?
With the 2" spacing from the radiator, and the shroud installed; you have a text book perfect setup for air flow.
Great to hear you've got 'er whipped!
I'll toast a beer to ya tonite!

 

[Scouty]

Is that a 6 or 7 blade fan? I thought you had a flex fan on there before?

I've just swapped out my 17" 6 blade fixed fan for a 18" 7 blade flex fan. I have yet to test it out. I'm running a new aluminum radiator with duel 1 1/4" rows.

Setup is:
aluminum duel 1 1/4" row radiator
fan shroud
18" 7 blade flex fan
180 degree thermostat
transmission cooler in front of radiator
12" electric pusher fan (880 cfm) in front of tranny cooler
power steering cooler

a few weeks ago when we had a few 100 degree days we went up to the strawberry trail. On highway 50 I couldn't get the temp over 180, on the trail the temp ran up to 210/220 while crawling. I've got a 727 automatic mated up to a 4:1 300, once I got the rmps up to about 2000 the temp stabilized right around 205, but if we went below that the temp went back up. Once we were back on the highway the temp dropped back to 180/185 and it was damn hot out. So I know the radiator flows the water, the problem is pulling enough air. Hoping the larger fan and curved blades will pull more cfms at lower rpms.

 

[Lou]

The radiator I bought from IH Parts America is the 2- 1” tube unit as what I had determined is that the 1-1/4” tube unit made fitment pretty cramped. When I installed the radiator and pump last weekend I found that the oem clutch was within ¼” of the radiator, to close for me. The adapter I got from jegs to eliminate the clutch and save the oem 7 blade fan was also too thick to install. I made a quick trip to four places that afternoon and found the hayden seven blade, 17” flex fan and installed it. It worked fine but I knew I needed an 18” fan. As I thought about it further I figured that the flex fan flattens as it speeds up and pulls less air. A fixed fan would just pull more air as its speed increased and that’s what I was after, air flow. As this motor almost never sees 3500 rpm I didn’t feel that anything would be lost to turbulence. I also found that the flex fan needs a 1-1/2” spacer in order for the blade tips to clear the belts. That left about 1” to the radiator and it was a pain to install the fan. This new derale 18” steel unit is six blades, only needed a ½” spacer, gave me two inches of radiator clearance and is easy enough to get the bolts installed. It also pulls a lot of air; I can faintly hear it whine at freeway speed. I expect to notice what scouty did, at rpms near 2000 or so I’ll have plenty of air flow and it will dump the heat. I also run a shroud but with a 195 deg thermostat. A temp of 205 while working the motor would be fine, I really didn’t worry much until it was heading for 220 and showing no sign of coming down with the trans in neutral and holding 2200 rpm.
My 727 has the 2.77 first gear instead of the 2.48 and I have the 3.15 tera-low kit in the transfer case. It does let me keep the rpm up. I’ve also got the big stacked plate trans cooler in front of the ac condenser in front of the radiator. I’ll be up wandering around crystal basin next weekend and intend to check this new setup out.
I did reverse the derale fan from what the sticker stated. That puts the cups facing the motor and the bent tips toward the radiator. I’m sure it’s correct, I went to the shed to check out my best shovel to make sure. It’s quiet and “seems” to pull more air at 2000 rpm + than the flex fan. That finding was certainly influenced by the money I’ve spent on fans, spacers, bolts, etc. I plan on unloading this stuff at the fall rallye swap meet.
Scouty, what do you use for a power steering cooler and how did you mount it?

 

[Scouty]

scouty, what do you use for a power steering cooler and how did you mount it?

I picked up a cheapy heavy duty universal oil cooler from autozone. It's about 10" x 5", I mounted it in front of the radiator right below the tranny cooler. It's light enough that it's ziptied to the grill.

Power steering cooler

Cooler is right below the pusher fan and tranny cooler

Here you can see where the tranny cooler and pusher fan are, cooler sits about an 1" from the radiator

Here's the 18" flex fan I got from summit

Here's the fan installed, using an aftermarket 1" spacer and the oem 1/2" spacer

Fan is 2" from the radiator

 

[Lou]

I took the truck for a test drive this afternoon up one of the tougher trails in the area. It was 4:30, just over 100 deg and I headed up sunrise blvd with a sprint up fair oaks rock trail. Lotsa traffic and sitting at lights with the ac on full. The temp never broke 200 deg and I run a 195 deg thermostat. It's looking good so far. I'm curious to see what effect this has on the fuel percolation problem I've been having. I'm sure they are related.

 

[Lou]

I loaded up the wife and trailer for a weekend run up to union valley in crystal basin. Heading up through placerville and above it was hot, probably pushing 100 and I was pretty much at wot much of the steeper grades, occassionaly in 2nd gear with some occasional faint pinging in 3rd. The highest temp it ever recorded was 209 which is just fine with me. We went up some of the smud powerline inspection roads around robbs peak and the highest temp crawling around there was about 205, again, just fine with me. As soon as any load is removed the temp drops down to 195. I also didn't experience the fuel percolation issue I've been having and overall the truck "feels" like it runs cooler. Even my feet think the floor and trans tunnel are cooler. I think I can put this issue to rest and go drive the damn thing. I see a quick trip to berlin-ichthyosaur coming this fall. Thanks again for all the input here, I'm good for a beer at the lake francis rally in October!!

 

[Monte Lauer]

Mr. Mayben, here is a picture of pink's newest setup. The radiator came to me from a very generous individual who wanted to help suppport maranda's addiction.

Along with the new radiator/fan setup I also installed a new high volume water pump. More cool hoses are on the way.

 

[Michael Mayben]

That is way too nice for pink!

Excellent work on that shroud/fan mount, was that part of the radiator combo from the fabricator or a separate item?

Do I see some silicone hoses lay on the floor?

 

[Monte Lauer]

that is way too nice for pink!

Excellent work on that shroud/fan mount, was that part of the radiator combo from the fabricator or a separate item?

Do I see some silicone hoses lay on the floor?

The fan/shroud combo came with the radiator.

Yes, those are the old silicone hoses. My aerospace friend is making me some new ones, he says the new ones will probably be red instead of blue.

 

[Monte Lauer]

Hoses are connected and the cooling system is burped. I let the engine temp hit 220* before I turned on the fans, moments later it dropped to 170*. I let the engine idle for about an hour at 1500 rpm, the temp stayed at a constant 170*.

 

[Michael Mayben]

hoses are connected and the cooling system is burped. I let the engine temp hit 220* before I turned on the fans, moments later it dropped to 170*. I let the engine idle for about an hour at 1500 rpm, the temp stayed at a constant 170*.

So that part is done!

How'd the rest of the motor turn out after the head gasket work? Any other issues?