mystery coolant hose
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Joined: Jun 2004
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From: 1987- L98, auto OH
mystery coolant hose
Ok, this is a bit different than I have run into before. I am replacing all the hoses on my 1987 L98. I have one that looks a lot like 3/8 inch fuel line hose and it's in a different location as well. This thing comes off the passenger side rear intake manifold with a metal line for a few inches, then the small rubber hose clamps there and continues for maybe a foot. It hooks into a metal hose (which itself is bolted to the passenger side of the engine compartment) and the metal line is joined to a short rubber line that in turn connects to the metal line that goes back to the upper heater hose. Obviously this is NOT fuel line, but a coolant line of some sort.
What is this thing for? And better yet, can I use regular fuel line to replace it? It is obviously smaller than the regular 1/2 inch heater type of hose. It does not show up on my Chevy dealer's pictoral hose printout that he gave me. I want to use the right line and since this small hose has a bulge on the side of it...my Vette is grounded until I get this sorted out.
Thanks for any help or advice!
Brad
What is this thing for? And better yet, can I use regular fuel line to replace it? It is obviously smaller than the regular 1/2 inch heater type of hose. It does not show up on my Chevy dealer's pictoral hose printout that he gave me. I want to use the right line and since this small hose has a bulge on the side of it...my Vette is grounded until I get this sorted out.
Thanks for any help or advice!
Brad
Melting Slicks
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From: What did the 5 fingers say to the face? SLAP!!
Originally Posted by scorp508
It is a coolant line there to help prevent overheating of the aluminum heads by promoting coolant circulation at the back of the intake. 
Hey something just clicked. My cast iron 86 has this line, but 85's don't. I read in a post the other day where the redisgned intake for the aluminum heads was introduced in the beginning of '86, long before the aluminum heads arrived. Makes sense now.
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From: 1987- L98, auto OH
Thanks guys! Cleared up the mystery for me. I'll drop by the autoparts store. I've never seen a coolant line this small before. The only sizes I've been offered by the parts guys is the 1/2, 5/8 and 3/4. Guess I took for granted that they were the only sizes they carried. I'll find out tomorrow. Thanks!
Brad
Brad
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From: SE NY
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If you look at the intake base to head gaskets on my '88 they only have small holes for steak to escape as needed and maybe a little coolant to pass.
That small coolant hose simply carries off any steam or coolant from the rear of the heads, as Brian stated. Fuel line hose should work fine there.
That small coolant hose simply carries off any steam or coolant from the rear of the heads, as Brian stated. Fuel line hose should work fine there.
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Joined: Aug 2004
Posts: 55
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From: Canyon Lake California
Heater hose
I've had trouble finding that hose for my '88 also. I have been forced to use fuel line instead but that is not a good long term solution. After a year or two, the fuel hose will start leaking where it connects to the metal pipe. I suspect that the high temperatures and the chemicals in the coolant attack the rubber in the fuel line. This process causes the rubber to harden and eventually leads to cracking.
I hate to admit it but, I am still running fuel line in that location. If someone finds a good source for coolant line in that diameter, I'll buy it and get that fuel line out of there.
I hate to admit it but, I am still running fuel line in that location. If someone finds a good source for coolant line in that diameter, I'll buy it and get that fuel line out of there.
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From: Hartford WI
Originally Posted by 65Z01
If you look at the intake base to head gaskets on my '88 they only have small holes for steak to escape as needed and maybe a little coolant to pass.
That small coolant hose simply carries off any steam or coolant from the rear of the heads, as Brian stated. Fuel line hose should work fine there.
That small coolant hose simply carries off any steam or coolant from the rear of the heads, as Brian stated. Fuel line hose should work fine there.
I have that same hose on my 91. How would I go about blocking it off completely since my new intakes do not have that hole?
Last edited by aklim; Aug 10, 2004 at 02:07 PM.
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From: 1987- L98, auto OH
Well, going to the auto parts store was a bust. They looked at me as if I had snakes growing out of my head. I don't think they believed me on the size of the hose. I was shown different preformed hoses of about the same size, but none was long enough or straight enough for the job. I was then told that 1/2 inch hose is the smallest there is and that was the end of the conversation. This is smaller than 1/2 and I'd guess it was about 3/8 or so.
I did go to our fast and friendly Chevy dealer who printed me out yet another exploded diagram of the hoses on my 1987 ... this time from a different angle. We both agreed after studying it that it is impossible to determine which hose it is from GM's diagram! At least he didn't think I was crazy.
I'm going to check into some different hose for this location. If I find anything promising. I'll let you know.
Brad
I did go to our fast and friendly Chevy dealer who printed me out yet another exploded diagram of the hoses on my 1987 ... this time from a different angle. We both agreed after studying it that it is impossible to determine which hose it is from GM's diagram! At least he didn't think I was crazy.
I'm going to check into some different hose for this location. If I find anything promising. I'll let you know.
Brad
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From: Boston, MA
Here is some good news for you. My 84-87 parts illustration book has it.
1987 "Y" ENGINE ASM-5.7L V8 (L98/5.7-8)-PART II
0.000-GROUP
Pages 0-12 & 0-13
(6-87)
106. TUBING, Manif Vpr (5/16)......8.964
107. CLAMP, Manif Vpr Hose (1/2-13/16)......8.948
108. HOSE, MANIF Vpr (7.9 Mm)......8.962
The TUBING is the metal part and the HOSE is the rubber part. The problem is that it lists no "normal" GM part #, just the numerical one there at the end.
1987 "Y" ENGINE ASM-5.7L V8 (L98/5.7-8)-PART II
0.000-GROUP
Pages 0-12 & 0-13
(6-87)
106. TUBING, Manif Vpr (5/16)......8.964
107. CLAMP, Manif Vpr Hose (1/2-13/16)......8.948
108. HOSE, MANIF Vpr (7.9 Mm)......8.962
The TUBING is the metal part and the HOSE is the rubber part. The problem is that it lists no "normal" GM part #, just the numerical one there at the end.
Last edited by scorp508; Aug 10, 2004 at 11:50 PM.
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Joined: Aug 2004
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From: Canyon Lake California
That drawing is a big help. Thanks for posting it. Now we all know which hose we are chasing. That number in the drawing I think has something to do with the GM warehouse location.
It was many years ago, but now I remember the guy at the Chevy parts counter telling me that the hose we're talking about comes from "general stock"... no GM part number. He said their mechanics have a roll of it and they just cut what they need. I asked him if I could buy some and he said he's not allowed to sell the stuff the mechanics use. It's not part of his inventory. He suggested that I go to any parts store and buy the length I need from them. Of course, that's easier said than done. With such a small diameter, everyone I went to wanted to sell fuel line.
In other words, the search continues.
It was many years ago, but now I remember the guy at the Chevy parts counter telling me that the hose we're talking about comes from "general stock"... no GM part number. He said their mechanics have a roll of it and they just cut what they need. I asked him if I could buy some and he said he's not allowed to sell the stuff the mechanics use. It's not part of his inventory. He suggested that I go to any parts store and buy the length I need from them. Of course, that's easier said than done. With such a small diameter, everyone I went to wanted to sell fuel line.
In other words, the search continues.
Melting Slicks
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From: What did the 5 fingers say to the face? SLAP!!
Originally Posted by scorp508
107. CLAMP, Manif Vpr Hose (1/2-13/16)......8.948
The hose doesn't need to be formed. Just buy a long enough piece of 1/2" heater hose and be done with it.
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From: 1987- L98, auto OH
Ok, I've tried various AN type braided hoses with no success. The -04AN is too small and the -06AN is too large. This hose is smaller than 1/2 inch. I took my mic out and checked the size of the metal line-- exactly 5/16 in diameter. For now, I am going to get some 5/16 fuel line, but not the regular stuff. I'm picking up the stuff rated for fuel injection (holds 40+ lbs pressure) and that should work for now.
I appreciate the diagram post. It is the same exploded view my GM parts guy printed out, but we couldn't quite tell the exact hose to order. I will talk with him again on this and see if he can order it. For now, the 5/16 high pressure/fuel injection hose will have to do. If you try this, I would make sure the parts people don't give you the regular hose, but definately the fuel injection kind. If anyone finds the "real stuff" let us know. Again, thanks Scorp, you da man with the diagram!
Brad
I appreciate the diagram post. It is the same exploded view my GM parts guy printed out, but we couldn't quite tell the exact hose to order. I will talk with him again on this and see if he can order it. For now, the 5/16 high pressure/fuel injection hose will have to do. If you try this, I would make sure the parts people don't give you the regular hose, but definately the fuel injection kind. If anyone finds the "real stuff" let us know. Again, thanks Scorp, you da man with the diagram!
Brad