Odd radiator and routing question

#1

OK, so I just got this 1987 325IS. The prior owner was working on the cooling system and gave up, so I am finishing it.

They get a radiator from a source familiar with SE30’s purportedly, but here is the issue. It appears to me that a stock radiator has the radiator inlet on the passenger side, which means that the water comes out of the thermostat neck and goes to the top of the radiator on the passenger side. The water flows downward through the radiator, and the radiator outlet is on the bottom of the driver’s side, which then flows to the water pump suction side.

This radiator is inverted, meaning that the water will have to flow out of the thermostat neck, into the bottom of the driver’s side of the radiator, the pump will need to work to push the entire column of water up through the radiator, and then the fluid will go out the outlet on the top of the driver’s side, then to the water pump.

This seems odd. I have never seen a water pump have to push the column of water up the radiator. Usually the pump pumps in the top of the radiator, the water exits the bottom.

Can anyone shed light on this? This radiator is purportedly “the good stuff” for running a SE30. Please let me know any thoughts.

-Scott

#2

The pump pushes water into the block. Pump > block > head > tstat housing > radiator. As near as I can figure, it should not matter if the water goes from the block to the top of the radiator, or block to the bottom of the radiator.

Below is early model plumbing. I’m not very familiar with late model, but I’m pretty sure that the pump and radiator are different.

#3

Why would it not matter? In the stock routing, the water pump, after it pumps Pump > block > head > tstat housing would then easily find its way in the top of the radiator, having to pump “uphill” only the water that is in the upper radiator hose. If the pump has to pump Pump > block > head > tstat housing and then pump into the bottom of the radiator, now the water pump also has to pump “uphill” the entire column of water that is in the radiator, instead just the water that is in the upper radiator hose.

Am I confused? It seems like the pump has to work a lot harder that way.

-Scott

#4

You’re confused.

The water starts and ends at the same place. No matter what path it gets there the sum of up and down is the same. In this case work done requires a change in potential energy. That requires a change in elevation between start and finish. If start and finish are in the same place, then net Work done against gravity is zero.

Work done is really a matter of pushing the coolant thru the system.

I’m better at physics then I am at motors.

#5

Sounds like you have a late model radiator. On the late model radiator the upper hose connects on the drivers side, and the lower runs through the cooling pipe across the front to the engine then connects on the passenger side. If you want to make it work on the 87 you have to change to the late model cooling system. Personally I prefer the early style.

“This radiator is purportedly “the good stuff” for running a SE30” Does this mean that it is an aluminum radiator. They do not make an aluminum radiator for early models.

A stock early model replacement will have no problem keeping the car cool on the hottest of days. So long as you have a good electric fan to keep it cool while sitting on the pre-grid or while stopped under red flag.

#6

Looks like I need a new radiator. I have one on order from NAPA, aluminum core, plastic tanks.

I am going with no radiator fan. I’ll just shut the car down on a red flag.

-Scott

#7

BigKeyserSoze wrote:

[quote]I am going with no radiator fan. I’ll just shut the car down on a red flag.

-Scott[/quote]
Your call, of course. But I think you might appreciate the ability to idle on grid on those occasions when the guy in DE2 has to get pulled out of the weeds right after the grid guy calls the 3 minute. Or when you have a pesky hard start condition. Or a weak battery.

Hypothetically speaking, of course.

Why not just buy the cross-over pipe and convert the cooling system to late style? Seems like that would be cheaper than a new stock rad.

#8

Steve D wrote:

[quote]BigKeyserSoze wrote:

[quote]I am going with no radiator fan. I’ll just shut the car down on a red flag.

-Scott[/quote]
Your call, of course. But I think you might appreciate the ability to idle on grid on those occasions when the guy in DE2 has to get pulled out of the weeds right after the grid guy calls the 3 minute. Or when you have a pesky hard start condition. Or a weak battery.

Hypothetically speaking, of course.

Why not just buy the cross-over pipe and convert the cooling system to late style? Seems like that would be cheaper than a new stock rad.[/quote]

It can be done, but the threaded holes for mounting the coolant pipe are absent on early car, so your looking at a new upper timing cover too. At least I think it mounts to the upper timing cover. I should know this I did two timing belts on late model cars the weekend before last.

Either way swapping systems is more trouble then its worth. Since you would also have to change the water pump and all the hoses, not to mention the expansion tank is on the opposite side and is connected with the stupid and expensive T hose.

#9

Oh yea, I almost forgot, the filler tank. I think it is a new model part, too. I am going to tap the filler tank into where the return line from the heater used to come back into the thermostat housing. Will that work?

#10

BigKeyserSoze wrote:

Best option would be to get the correct expansion tank, and use the correct hose. The expansion tank hose on an early model connects back to the water pump.

here’s a diagram:

No. Description Supplement Qty From Up To Part Number Price Notes
01 WATER HOSE 1 09/1987 11531279895 $37.84
02 WATER HOSE 1 09/1987 11531286914 $23.28
03 WATER HOSE 1 09/1987 11531287651 $37.73
04 Hose clamp L42-48 4 09/1987 07129952119 $1.15
For vehicles with
Air conditioning
and
Tropical version
05 Bracket 1 09/1987 11531279946 $0.75
06 Flat washer 6,4 1 09/1987 07119931044 $0.58
07 Hex nut M6-8-ZNS 1 09/1987 07119922832 ENDED
07 Hex nut M6 1 09/1987 07119905543 $0.38
08 Hose clamp 1 09/1987 11531714433 $2.39
09 WATER HOSE 1 09/1987 11531289257 $22.09
10 Hose clamp L32-38 2 09/1987 07129952115 $1.27
11 Clamp D=28/6,4 1 09/1987 11531267334 $1.61
12 WAVE WASHER B6 1 09/1987 07119932099 $0.38
12 WAVE WASHER B6-ZNS3 1 09/1987 07119904496 ENDED
13 Hex bolt M6X60 1 09/1987 07119912351 $0.80
14 WATER HOSE 1 09/1987 13541705568 $11.11
15 WATER HOSE 1 09/1987 13541289976 $12.07
16 Hose clamp L15-18 4 09/1987 11151727509 $1.02
17 WATER HOSE INLET 1 09/1987 64211380527 $17.64
18 WATER HOSE OUTLET 1 09/1987 11531289377 $22.09
19 Hose clamp L32-38 2 09/1987 07129952115 $1.27
20 Hose clamp L16-30 2 09/1987 64218367179 $1.07
21 Clamp D=28/6,4 2 09/1987 11531267334 $1.61
21 Bow 1 09/1987 11531277934 $3.15

Sounds like the PO of your car started to do the conversion then stopped. Post some pics of what you’re working with

#11

Scott - I am taking apart a 1984 e chassis and I think I still have the expansion tank. It’s your for the cost of postage if you want it.

#12

I also have a front mount fan I will sent you for shipping cost. You really want to have an auxillary fan for those hot days on grid. You can buy a $20 fan relay from Autozone/Advance and run to the AC switch (yellow lead). Pictures to do this are in an old post.
Ed

#13

I have run on some of the hottest days in the SE and have no aux or main fan. It’s never been a problem so I wouldn’t worry about it unless you just want one. You typically get a 1 minute call or something close to that while on grid so there’s no need to keep the car running for a long time. Let it warm up, shut it off, and then fire it up at 1 minute.

I do shut the car off on a red flag. Make sure you have a good starter and battery (ask Gee-ger).

#14

OK, literally sitting under the hood of the car (not bolted down) is a filler tank that looks like the round one posted by 87is man earlier. The problem is, the water pump on this car has been changed by the prior owner, and there is no secondary tee in the water pump where the filler tank would join in. So what do I do now? I am guessing that the filler tank needs to be installed on the suction side of the system, correct? Also, that filler tank has a small plastic barb on it that looks like it should be heading off to an expansion tank, but I do not believe I have one of those. Today I ordered a stock replacement radiator for the car, which has the radiator inlet on the passenger top, and the outlet on the driver side low. I also ordered new hoses, so that part will be solved, but how do I get a filler tank in line?

#15

BigKeyserSoze wrote:

You need to order an early model water pump!! Lucky for you they aren’t very expensive. The smaller inlet into the tank is where the overflow from the radiatior enters. There will also be a small hose inlet on the top right of the radiator. The other hose barb by the cap is where you want to attach your overflow line into a catch bottle that you will have to add. I ran mine into an old oil bottle that I mounted where the washer fluid tank used to be.

#16

I am told that the early style cooling system rips hoses on the pulleys because of the engine torque, and has other issues. Anyone heard of this? Seems to me the easiest way to handle this is to get the proper water pump, the standard radiator, stock hoses, and put it all on, but first I wanted to see if the hoses really rip and have those other issues.

-Scott

#17

BigKeyserSoze wrote:

[quote]I am told that the early style cooling system rips hoses on the pulleys because of the engine torque, and has other issues. Anyone heard of this? Seems to me the easiest way to handle this is to get the proper water pump, the standard radiator, stock hoses, and put it all on, but first I wanted to see if the hoses really rip and have those other issues.

-Scott[/quote]

Maybe with crappy stock motor mounts and running a stock fan. With the motor mounts we run and by making sure the lower radiator hose is in its bracket on the frame rail you won’t have a problem. I have not read the 2010 rules but I’m not sure it says you can change the cooling system form early to late.

IMO the early system is much better the way we setup our cars with no fan and poly bushings, need to change a v-belt no need to remove a coolant pipe and hoses. Need to change the cap and rotor no need to remove a coolant pipe and hoses

#18

BigKeyserSoze wrote:

[quote]I am told that the early style cooling system rips hoses on the pulleys because of the engine torque, and has other issues. Anyone heard of this? Seems to me the easiest way to handle this is to get the proper water pump, the standard radiator, stock hoses, and put it all on, but first I wanted to see if the hoses really rip and have those other issues.
-Scott[/quote]

In addition to the lower radiator hose clamp that keeps the hose away from the alternator pully, you can put a zip tie on the hose to pull it a little farther away yet.
-Scott

#19

2 '87s, 100+ track sessions, including racing, with no ripped hoses. One small hose failure, but that has been it. We now have a '87 and '91 and I like the early system better - the hard line (metal section on timing cover) is a PITA.
Ed

#20

Steve, I do need that coolant recovery tank and fittings if you can send it. I will happily pay postage. Send to Scott McKay, 311 41st Street NE, Bradenton, FL 34208. If you have the mounting bolts and bracket, that would also be good.

Also, if you have a third brake light for one of these cars, I’d take that too.

Thanks in advance for your help.