92-96 heater hose control valve - GM 10188036

[David L.]

Does anyone know the real purpose of the heater hose control valve, GM # 10188036, used on 92-96 Corvettes, 93-97 Camaro Z28's, and other GM models?

Since the heater hose assembly in my 94 Z28 is 20 years old I decided to replace the rubber hose parts on the assembly. I dissected the original valve (made of plastic) from my 94 Z28. I can provide a photo, if necessary. The valve fits on the 3/4" dia. inlet hose and has a disk with a 0.25" dia. hole attached to a very weak spring. During low rpm's the spring allows for flow around the disk as well as through the 0.25" dia. hole. At higher rpm's the spring closes and only allows flow through the 0.25" dia. hole.

I do not want to use the GM plastic valve. I would rather use a valve made of metal. The Fords use some kind plug with a small hole that is inserted into the heater hose and then clamped with a worm gear clamp.

I have done some research on the web and the general consensus seems to be that the valve restricts flow to reduce pressure to the heater core at high RPM's. In my opinion the valve only reduces the pressure through the 0.25" hole. After the flow passes through the small hole the pressure increases back to what it original was (Bernoulli's Principle, see attachment below). The flow rate (Q) stays the same through the hose assembly. The smaller cross sectional area (A) through the 0.25" dia. causes the velocity (V) to increase resulting in a very temporary pressure reduction.
Q = A1 X V1 = A2 X V2 (continuity equation).
You can calculate this temporary pressure reduction using Bernoulli's Equation which you can find on the web or in a fluid mechanics text book.

I would appreciate any comments.

Dave

[Joe L.]

Re: 92-96 heater hose control valve - GM 10188036

Does anyone know the real purpose of the heater hose control valve, GM # 10188036, used on 92-96 Corvettes, 93-97 Camaro Z28's, and other GM models?

Since the heater hose assembly in my 94 Z28 is 20 years old I decided to replace the rubber hose parts on the assembly. I dissected the original valve (made of plastic) from my 94 Z28. I can provide a photo, if necessary. The valve fits on the 3/4" dia. inlet hose and has a disk with a 0.25" dia. hole attached to a very weak spring. During low rpm's the spring allows for flow around the disk as well as through the 0.25" dia. hole. At higher rpm's the spring closes and only allows flow through the 0.25" dia. hole.

I do not want to use the GM plastic valve. I would rather use a valve made of metal. The Fords use some kind plug with a small hole that is inserted into the heater hose and then clamped with a worm gear clamp.

I have done some research on the web and the general consensus seems to be that the valve restricts flow to reduce pressure to the heater core at high RPM's. In my opinion the valve only reduces the pressure through the 0.25" hole. After the flow passes through the small hole the pressure increases back to what it original was (Bernoulli's Principle, see attachment below). The flow rate (Q) stays the same through the hose assembly. The smaller cross sectional area (A) through the 0.25" dia. causes the velocity (V) to increase resulting in a very temporary pressure reduction.
Q = A1 X V1 = A2 X V2 (continuity equation).
You can calculate this temporary pressure reduction using Bernoulli's Equation which you can find on the web or in a fluid mechanics text book.

I would appreciate any comments.

Dave

Dave------


The GM #10188036 valve was not used on Corvettes although it was used on 1993-97 Camaros, including Z-28. 1992-96 Corvettes used valve GM #10157988. Both valves are similar in configuration but I assume there is a difference in either calibration or hose nipple size.

As far as obtaining a valve of metal construction, I think you'll be looking for a long while and never find one. I highly doubt that a metal replacement valve for this application exists now or will exist in the future.

I don't like plastic for these kind of cooling system parts myself but finding alternatives is virtually impossible.

[Terry M.]

Re: 92-96 heater hose control valve - GM 10188036

The B & D-body (Impala, Caprice,, Roadmaster, Fleetwood) with Gen II LT1 engine using reverse flow cooling, like 1992 to 1996 Corvette use one of these plastic valves. The reported function is to reduce the flow of coolant through the heater at WOT. Since some of these cars see high mileage deterioration of the plastic is common. I am not going to get into an argument about the engineering of this; however some participants in the forums for these cars (www.impallassforum.com) have eliminated this valve without apparent harm.

Some others have "recreated" the part from copper fittings available at any big box builder's store or your local hardware store. That has worked well for those who value function over form. I just searched that forum for a thread on the subject, but couldn't quickly find it. I believe I have a link for that mod on my desktop at home, but that will have to wait for the end of my journey home from Bowling Green.

My Caprice DDs, both with well over 250K on them, still have plastic valves, but IIRC I have replaced one of them with a prat from Chevrolet. If It matters I can get that part number at home, but I doubt it is available any longer. I do have a lifetime supply; none for sale.

[David L.]

Re: 92-96 heater hose control valve - GM 10188036

I bought a plastic GM 10188036 (AC Delco 15-5511) from my local Chevrolet dealer. It measures 3.60" in overall length and is for a 3/4" heater hose.

I thought that the 92-96 Corvette valve was the same but I guess not. The 92-96 Corvette valve (GM # 10157988, AC Delco #15-5423) looks very similar as Joe stated.

I also bought a aluminum restrictor (2.32" in overall length for 5/8" heater hose) for $10 from an aftermarket vendor (left side in bottom photo). The hole in the aluminum restrictor measures 0.30" in diameter. I will need to use two 3/4" to 5/8" metal connectors to use this restrictor. I do not like plastic.

My 94 Z28 has the reverse flow cooling as Terry mentioned. Also, the inlet heater hose is 3/4" while the outlet hose is 5/8" just the opposite whn compared to my 66 Corvette.

Back to my original question. How does this valve (aka, restrictor) reduce the flow through the heater core? What about the continuity equation (Q = A1 X V1 = A2 X V2 = A3 X V3).

Does WOT mean wide open throttle? The flow rate ("Q" in gal./min) through the water pump is substantially higher at wide open throttle. The water pump flow rate might be about 5-10 gal./min at idle and might be about 30-40 gal./min. at wide open throttle.

Dave

[Joe L.]

Re: 92-96 heater hose control valve - GM 10188036

The B & D-body (Impala, Caprice,, Roadmaster, Fleetwood) with Gen II LT1 engine using reverse flow cooling, like 1992 to 1996 Corvette use one of these plastic valves. The reported function is to reduce the flow of coolant through the heater at WOT. Since some of these cars see high mileage deterioration of the plastic is common. I am not going to get into an argument about the engineering of this; however some participants in the forums for these cars (www.impallassforum.com) have eliminated this valve without apparent harm.

Some others have "recreated" the part from copper fittings available at any big box builder's store or your local hardware store. That has worked well for those who value function over form. I just searched that forum for a thread on the subject, but couldn't quickly find it. I believe I have a link for that mod on my desktop at home, but that will have to wait for the end of my journey home from Bowling Green.

My Caprice DDs, both with well over 250K on them, still have plastic valves, but IIRC I have replaced one of them with a prat from Chevrolet. If It matters I can get that part number at home, but I doubt it is available any longer. I do have a lifetime supply; none for sale.

Terry-----


The B & D GM cars use the same valve as Corvette-----GM #10157988. You can still buy as many of these as you want from GM or Delco dealers.

[Joe L.]

Re: 92-96 heater hose control valve - GM 10188036

I bought a plastic GM 10188036 (AC Delco 15-5511) from my local Chevrolet dealer. It measures 3.60" in overall length and is for a 3/4" heater hose.

I thought that the 92-96 Corvette valve was the same but I guess not. The 92-96 Corvette valve (GM # 10157988, AC Delco #15-5423) looks very similar as Joe stated.

I also bought a aluminum restrictor (2.32" in overall length for 5/8" heater hose) for $10 from an aftermarket vendor (left side in bottom photo). The hole in the aluminum restrictor measures 0.30" in diameter. I will need to use two 3/4" to 5/8" metal connectors to use this restrictor. I do not like plastic.

My 94 Z28 has the reverse flow cooling as Terry mentioned. Also, the inlet heater hose is 3/4" while the outlet hose is 5/8" just the opposite whn compared to my 66 Corvette.

Back to my original question. How does this valve (aka, restrictor) reduce the flow through the heater core? What about the continuity equation (Q = A1 X V1 = A2 X V2 = A3 X V3).

Does WOT mean wide open throttle? The flow rate ("Q" in gal./min) through the water pump is substantially higher at wide open throttle. The water pump flow rate might be about 5-10 gal./min at idle and might be about 30-40 gal./min. at wide open throttle.

Dave

Dave-------



The 10188036 valve was used for many applications other than those with Gen II small blocks. Primarily, these include applications using the 3.8L V-6.

[David L.]

Re: 92-96 heater hose control valve - GM 10188036

Here are photos on my dissected 94 Z28 heater control valve, GM # 10188036 in Gr. 8.866 in my 1993 Camaro Parts Catalog (Nov. 1992). The center plastic tube measures 1.16" O.D. and 1.05" I.D. The bottom photo has the restictor and spring in the 1.05" I.D. plastic tube.

Dave

[Terry M.]

Re: 92-96 heater hose control valve - GM 10188036

Dave,

WOT = Wide Open Throtle

For B & D bodies:
10157988 coolant flow control valve 8.866 (also ACDelco 15-5423)

I have no idea about the engineering of this part; and have only anecdotal information about its function. My take is that if it was not needed, it would not have been installed. Content cost savings is very important to OEMs.

I am unable to find the details of the B & D-body modification to this part that I referenced in my earlier post. I will continue to look.

[David L.]

Re: 92-96 heater hose control valve - GM 10188036

Dave,

WOT = Wide Open Throtle

For B & D bodies:
10157988 coolant flow control valve 8.866 (also ACDelco 15-5423)

I have no idea about the engineering of this part; and have only anecdotal information about its function. My take is that if it was not needed, it would not have been installed. Content cost savings is very important to OEMs.

I am unable to find the details of the B & D-body modification to this part that I referenced in my earlier post. I will continue to look.

Terry,

I have never used the $100 word "anecdotal". Isn't that a word that a lawyer would use?

At this point my inclination is to use the aftermarket 2.32" long aluminum restrictor with the 0.30" hole along with two 3/4" to 5/8" metal connectors instead of the 10188036 valve that I bought from the Chevrolet dealer. I just do not like to use plastic even though the original plastic valve still appeared to be in good condition (until I dissected it) after 20 years with 136,000 miles. I still would like to find out the real engineering reason why these valves valve are used.

Thanks,

Dave

[Terry M.]

Re: 92-96 heater hose control valve - GM 10188036

Terry,

I have never used the $100 word "anecdotal". Isn't that a word that a lawyer would use?

At this point my inclination is to use the aftermarket 2.32" long aluminum restrictor with the 0.30" hole along with two 3/4" to 5/8" metal connectors instead of the 10188036 valve that I bought from the Chevrolet dealer. I just do not like to use plastic even though the original plastic valve still appeared to be in good condition (until I dissected it) after 20 years with 136,000 miles. I still would like to find out the real engineering reason why these valves valve are used.

Thanks,

Dave

Actually anecdotal is a word someone who worked in research for four years would and does use. It is exactly what most of the "data" on this board is made of.

This may have some information on it. I am too lazy to read it all:

http://forum.theherd.com/topic.asp?TOPIC_ID=112

There was an SAE paper presented back in 1992 on the Gen II LT1 engine and its design. As I remember the author was from India. I would expect that paper to still be available from SAE, but I can not guarantee you that there is reference to that valve in there either.

[Joe L.]

Re: 92-96 heater hose control valve - GM 10188036

Actually anecdotal is a word someone who worked in research for four years would and does use. It is exactly what most of the "data" on this board is made of.

This may have some information on it. I am too lazy to read it all:

http://forum.theherd.com/topic.asp?TOPIC_ID=112

There was an SAE paper presented back in 1992 on the Gen II LT1 engine and its design. As I remember the author was from India. I would expect that paper to still be available from SAE, but I can not guarantee you that there is reference to that valve in there either.

Terry------


His name was Anil Kulkarni. He was the lead GM Powertrain Engineer for the Gen II small block. I, too, doubt there will be anything in his writings regarding the heater valve.

[David L.]

Re: 92-96 heater hose control valve - GM 10188036

Terry,

Thanks for the link for the LT1 reverse flow cooling system. I remember reading something similar (if not the same) back when I bought my 94 Z28 in 2002. I just printed it out to read it more carefully.

This morning I called one of my former civil engineering co-workers that I worked with in the last decade. He is coming to our house for dinner this Thursday so we can talk more about the heater hose restrictor. Over the phone he suggested that the engine cooling system might be somewhat similar to a city water supply pipe system but with only two simple loops - the radiator hose loop and the heater hose loop. Both loops are circulated by the same pump and have different flows based on head loss, pipe length, roughness coefficient, pipe diameter, and RPM's. The Hardy-Cross Method could possibly be used to analyze each loop be it would be quite difficult since the two loops are not simple pipes. The flow through the radiator, engine block, cyl. heads, and heater core obviously can not be treated as pipes. When I get a chance I might try doing a simplified computation using the Hardy-Cross Method and assuming the two loops are simple 5/8", 3/4", 1 5/16", 1/4", dia. "pipes" just to see what the flow is through the 0.25" opening at various RPM's (idle and full throttle).

Dave

[Terry M.]

Re: 92-96 heater hose control valve - GM 10188036

Terry,

Thanks for the link for the LT1 reverse flow cooling system. I remember reading something similar (if not the same) back when I bought my 94 Z28 in 2002. I just printed it out to read it more carefully.

This morning I called one of my former civil engineering co-workers that I worked with in the last decade. He is coming to our house for dinner this Thursday so we can talk more about the heater hose restrictor. Over the phone he suggested that the engine cooling system might be somewhat similar to a city water supply pipe system but with only two simple loops - the radiator hose loop and the heater hose loop. Both loops are circulated by the same pump and have different flows based on head loss, pipe length, roughness coefficient, pipe diameter, and RPM's. The Hardy-Cross Method could possibly be used to analyze each loop be it would be quite difficult since the two loops are not simple pipes. The flow through the radiator, engine block, cyl. heads, and heater core obviously can not be treated as pipes. When I get a chance I might try doing a simplified computation using the Hardy-Cross Method and assuming the two loops are simple 5/8", 3/4", 1 5/16", 1/4", dia. "pipes" just to see what the flow is through the 0.25" opening at various RPM's (idle and full throttle).

Dave

If the simplified system is two parallel paths one would want to restrict the heater loop in order to force most of the flow through the engine/radiator loop. Just a quick thought for late at night.

[David L.]

Re: 92-96 heater hose control valve - GM 10188036

Terry,

Restricting the heater loop to force most of the flow through the engine/radiator loop was one of the ideas that I found in while searching on the web last week but it was not the most popular.

There are actually 2 additional loops. The 3rd loop is from the from the back of the engine at the ends of the cylinder heads to the top right of the radiator. The 4th loop is from the water pump to the oil cooler at the oil filter adapter and then back to the lower left of the radiator. The 3rd and 4th loops are either 5/8" or 3/4".

Dave

[Terry M.]

Re: 92-96 heater hose control valve - GM 10188036

Terry,

Restricting the heater loop to force most of the flow through the engine/radiator loop was one of the ideas that I found in while searching on the web last week but it was not the most popular.

There are actually 2 additional loops. The 3rd loop is from the from the back of the engine at the ends of the cylinder heads to the top right of the radiator. The 4th loop is from the water pump to the oil cooler at the oil filter adapter and then back to the lower left of the radiator. The 3rd and 4th loops are either 5/8" or 3/4".

Dave

What you refer to as loop #3 is described as a steam vent in the FSM for the B & D-bodies. There is also a path for the coolant to flow through the throttle body on the B & D-bodies. I can not recall the path for the latter because I removed it from my cars so many years ago.