C4 Cooling Experts Please step in
Thread Starter
Premium Supporting Vendor
Joined: Oct 2004
Posts: 36,838
Likes: 438
From: Manassas Park VA
St. Jude Donor '07-'08,-'13-'14, '16-'17
C4 Cooling Experts Please step in
Hi Everyone,
We have been asked to produce these Braided hoses for the C4 Gen
http://forums.corvetteforum.com/show....php?t=1932089
Because I am not super familiar with the subtle differences across C4 Gen I have a question or two...
For 1984-1996 Corvettes the Dayco Part numbers for the C4 Radiator Hoses are,
71645 Upper Curved
71149 Upper Curved
71646 Lower
81031
My Questions are as follows:
Dayco lists these hoses for all years of the C4
1) Do all C4's have the same exact hoses, Do they all have the 4 listed?
2) The 81031 I assume is straight with a slight flex, no need for a molded piece???
Tks
Chip
We have been asked to produce these Braided hoses for the C4 Gen
http://forums.corvetteforum.com/show....php?t=1932089
Because I am not super familiar with the subtle differences across C4 Gen I have a question or two...
For 1984-1996 Corvettes the Dayco Part numbers for the C4 Radiator Hoses are,
71645 Upper Curved
71149 Upper Curved
71646 Lower
81031
My Questions are as follows:
Dayco lists these hoses for all years of the C4
1) Do all C4's have the same exact hoses, Do they all have the 4 listed?
2) The 81031 I assume is straight with a slight flex, no need for a molded piece???
Tks
Chip
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Joined: Mar 2004
Posts: 553
Likes: 6
From: Northern VA
Hi, beautiful braided hoses.
I'm not sure why but lower CONVERTIBLE C4 hoses are different and I sort of verified that when I just ordered a standard lower hose. I had to send it back then search for a CONVERTIBLE lower hose. Ended up buying the last 3 in stock from mid america. Now their site says SPECIAL ORDER
609-064 1985-87 Hose, radiator lower (Coupe) (GM) $36.99 In Stock
622-698 1986-87 Hose, lower radiator (Convertible) (GM) $46.99 Special Order Item
see http://www.mamotorworks.com/corvette?frame=3.931
Anyway I want 3 sets of both upper and lower when you make them. How will we know that you made them and that they are for sale?
Thanks and good luck
I'm not sure why but lower CONVERTIBLE C4 hoses are different and I sort of verified that when I just ordered a standard lower hose. I had to send it back then search for a CONVERTIBLE lower hose. Ended up buying the last 3 in stock from mid america. Now their site says SPECIAL ORDER
609-064 1985-87 Hose, radiator lower (Coupe) (GM) $36.99 In Stock
622-698 1986-87 Hose, lower radiator (Convertible) (GM) $46.99 Special Order Item
see http://www.mamotorworks.com/corvette?frame=3.931
Anyway I want 3 sets of both upper and lower when you make them. How will we know that you made them and that they are for sale?
Thanks and good luck
Thread Starter
Premium Supporting Vendor
Joined: Oct 2004
Posts: 36,838
Likes: 438
From: Manassas Park VA
St. Jude Donor '07-'08,-'13-'14, '16-'17
Hi, beautiful braided hoses.
I'm not sure why but lower CONVERTIBLE C4 hoses are different and I sort of verified that when I just ordered a standard lower hose. I had to send it back then search for a CONVERTIBLE lower hose. Ended up buying the last 3 in stock from mid america. Now their site says SPECIAL ORDER
609-064 1985-87 Hose, radiator lower (Coupe) (GM) $36.99 In Stock
622-698 1986-87 Hose, lower radiator (Convertible) (GM) $46.99 Special Order Item
see http://www.mamotorworks.com/corvette?frame=3.931
Anyway I want 3 sets of both upper and lower when you make them. How will we know that you made them and that they are for sale?
Thanks and good luck
I'm not sure why but lower CONVERTIBLE C4 hoses are different and I sort of verified that when I just ordered a standard lower hose. I had to send it back then search for a CONVERTIBLE lower hose. Ended up buying the last 3 in stock from mid america. Now their site says SPECIAL ORDER
609-064 1985-87 Hose, radiator lower (Coupe) (GM) $36.99 In Stock
622-698 1986-87 Hose, lower radiator (Convertible) (GM) $46.99 Special Order Item
see http://www.mamotorworks.com/corvette?frame=3.931
Anyway I want 3 sets of both upper and lower when you make them. How will we know that you made them and that they are for sale?
Thanks and good luck
I'll send you a personal PM. We'll also post it in C4 Gen and C4 PFS
Peace
Chip
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
There's a T fitting in the upper hose for 92-94 LT1's that supplies the throttle body coolant line. So those years have two upper hoses. Rad to T and T to water pump at the 'stat housing. The 95-96 upper hose is one piece and goes from the rad to the 'stat housing on the water pump. A single hose (for the 95-96) can easily be modded to work with the earlier years with a knife 
The lower hose should be the same for all LT1s&4s.
As always, YMMV tax tag title extra...
The lower hose should be the same for all LT1s&4s.
As always, YMMV tax tag title extra...
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
I changed my '84 to TPI and the neck, over the thermostat, is longer on the newer. I think I used the same hose but the fit is imperfect.
For inventory cost concerns, I doubt Dayco wants to carry an '84 only hose.
Are the kits together yet? Will these hoses last indefinitely?
For inventory cost concerns, I doubt Dayco wants to carry an '84 only hose.
Are the kits together yet? Will these hoses last indefinitely?
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
I am definitely interested in these. None of the drawings are correct for the 95 coupe upper hose. The upper hose comes off the radiator neck into an immediate 90* bend, goes across the radiator maybe 10-12 inches and then curves back to the engine. I recently bought both hoses and can give you part numbers if needed. Let me know if I can help.
