Getting to the reason this 78 GMC runs hotter then my last 78.

Bob Dunahugh

New member
Sep 17, 2012
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Winter is closing in. Down to 16 last night, up to a balmy 39 today. The GMC is in it's home at 70. Time to go looking. Drained the coolant so I could put my inspection camera in the radiator. As I suspected. Plenty of corrosion in the cross tubes. Then checked the radiator out of the burned 78. Perfectly clean. Answered that question. Next. Pull the water pump out to see if it's the correct higher volume pump. So since its out. And has about 12,000 miles on it. I'll replace it no matter what's there. Next. Put a new harmonic dampener in since the timing mark has moved. So since all this stuff is out. Put the new electrically controlled fan/clutch in that I got at the Elkhart GMCMI rally. So now. Bring on the heat next Summer. Bob Dunahugh
 
Bob,

Cool!

(I just couldn’t resist)

Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
Howell EFI + EBL + Electronic Distributor

>
> Winter is closing in. Down to 16 last night, up to a balmy 39 today. The GMC is in it's home at 70. Time to go looking. Drained the coolant so I could put my inspection camera in the radiator. As I suspected. Plenty of corrosion in the cross tubes. Then checked the radiator out of the burned 78. Perfectly clean. Answered that question. Next. Pull the water pump out to see if it's the correct higher volume pump. So since its out. And has about 12,000 miles on it. I'll replace it no matter what's there. Next. Put a new harmonic dampener in since the timing mark has moved. So since all this stuff is out. Put the new electrically controlled fan/clutch in that I got at the Elkhart GMCMI rally. So now. Bring on the heat next Summer. Bob Dunahugh
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While you're in that close, how old is your timing chain? Not much more excavating from there.
Rick Staples
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
 
Richard. The 403 was rebuilt by the PO in 1994. When I bought it in 2015. The engine had 1884 miles on the clock. Has about 12,000 miles now. The timing chain isn't of concern now. Normally you would have a good point. Bob Dunahugh

________________________________
From: Bob Dunahugh
Sent: Wednesday, November 22, 2017 10:47 PM
To: gmclist
Subject: Getting to the reason this 78 GMC runs hotter then my last 78.

Winter is closing in. Down to 16 last night, up to a balmy 39 today. The GMC is in it's home at 70. Time to go looking. Drained the coolant so I could put my inspection camera in the radiator. As I suspected. Plenty of corrosion in the cross tubes. Then checked the radiator out of the burned 78. Perfectly clean. Answered that question. Next. Pull the water pump out to see if it's the correct higher volume pump. So since its out. And has about 12,000 miles on it. I'll replace it no matter what's there. Next. Put a new harmonic dampener in since the timing mark has moved. So since all this stuff is out. Put the new electrically controlled fan/clutch in that I got at the Elkhart GMCMI rally. So now. Bring on the heat next Summer. Bob Dunahugh