Johnny. The outside fins can have separation from the outside of the co=
olant tubes that go horizontally across the radiator. This is simple to do =
by simply looking.. These outside fins also need to be inspected with the u=
se of a flashlight at night. Have someone shine a flashlight from the back =
of the radiator. Then have someone else at the front to look for areas tha=
t are plugged up with bugs. I have a bug screen in front of my radiator tha=
t I got from Jim K at Applied GMC. Compressed air, or water can be used to =
clean the bugs out. Our real problem is that we can't look inside our radia=
tors. I've tried mirrors. Didn't work. This camera inspection will see if =
there's corrosion on the inside that isn't going to be an obstruction to c=
oolant flow. The coolant needs to be removed for a clearer view inside. Plu=
s I don't want to find out the hard way if my camera is truly water proof. =
Bob Dunahugh Member GMCMI and Greater Midwest Classics ___________=
_____________________ From: Bob Dunahugh Sent: T=
hursday, January 4, 2018 9:13 PM To: gmclist Subject: R=
E: The stock temp gauge doesn't really tell you your operating temps. Why t=
hat's a problem Johnny. The problem s there are that the radiator =
should be full if the overflow tank is at it's correct level. Next. The cor=
rosion at the top could be drastically different farther down. The radiator=
s have drains at the bottom that is simple to open. Good thought though. =
Bob Dunahugh ________________________________ From: Bob Dunahugh =
Sent: Tuesday, January 2, 2018 5:08 PM To: gmcli=
st Subject: RE: The stock temp gauge doesn't really tell =
you your operating temps. Why that's a problem Mike K. Thanks. I t=
hink this is more of a problem then is generally thought. I pull higher GVW=
's more then most. And never had any add on items installed on our 403 GMC.=
Radiator inspections on attendees GMC's. Might make for a good tech sessi=
on at the GMCMI rally in Tucson. Line them up, and start checking with my i=
nspection camera. Drain pan, funnel, and the camera. At a cost of FREE. Go=
od idea, or not. Any input out there? Bob Dunahugh Ou=
r first 78 Royale came with a Digi panel. I knew my engine temps under all =
conditions. Then the fire. Bought another 78 Royale. But the Digi panel was=
n't being made at that time. Both GMC stock temp gauges read the same. But=
it didn't take long before I had a feeling that this second Royale was run=
ning hotter. No boil overs. Just didn't feel right. So on our next trip. I =
raise the engine cover several times to check the engine temp sender with =
an inferred temp reader. Found that this Royale was generally operating ab=
out 10 degrees hotter with the stock gauge reading in the normal range as =
compared to our first GMC. Jim at Applied GMC had started producing the Dig=
i panel. And had them at the GMCMI rally that we were going too. Installed =
the Digi panel at the rally. On the way home the panel also confirmed what=
I thought. So why the running hotter? Checked the thermostat. It was a goo=
d operating 180. But I changed to a proper 195. Fan clutch? Maybe. Well J=
im K at Applied started selling a fan clutch that is controlled by engine b=
lock sensors. I liked the idea that this system is more proactive in contro=
lling engine heat buildup. Plus I can turn the clutch on for the fan by a d=
ash mounted switch when I want. So I bought that fan clutch at the GMCMI ra=
lly. I had recently put on an aluminum 307 Olds intake manifold. So I knew=
the engine was clean inside. Did the engine have a car water pump? Don't k=
now. But even if there's a car pump. That's not the real big problem. Next =
I drained the radiator. Put my inspection camera in the radiator. Radiator=
's my problem. Looked heavily corroded at the crossover tubes. Going to put=
the radiator from the burned GMC in soon. Probably check/change water pump=
anyway while I'm doing other work in that area. Installing more gauges to =
look at isn't the best idea in my opinion. One. I want to be looking at th=
e road for safe driving. Two. The Digi panel has gages. But it's audible a=
larm is your best engine/trans protection. Bob Dunahugh 78 Royale
olant tubes that go horizontally across the radiator. This is simple to do =
by simply looking.. These outside fins also need to be inspected with the u=
se of a flashlight at night. Have someone shine a flashlight from the back =
of the radiator. Then have someone else at the front to look for areas tha=
t are plugged up with bugs. I have a bug screen in front of my radiator tha=
t I got from Jim K at Applied GMC. Compressed air, or water can be used to =
clean the bugs out. Our real problem is that we can't look inside our radia=
tors. I've tried mirrors. Didn't work. This camera inspection will see if =
there's corrosion on the inside that isn't going to be an obstruction to c=
oolant flow. The coolant needs to be removed for a clearer view inside. Plu=
s I don't want to find out the hard way if my camera is truly water proof. =
Bob Dunahugh Member GMCMI and Greater Midwest Classics ___________=
_____________________ From: Bob Dunahugh Sent: T=
hursday, January 4, 2018 9:13 PM To: gmclist Subject: R=
E: The stock temp gauge doesn't really tell you your operating temps. Why t=
hat's a problem Johnny. The problem s there are that the radiator =
should be full if the overflow tank is at it's correct level. Next. The cor=
rosion at the top could be drastically different farther down. The radiator=
s have drains at the bottom that is simple to open. Good thought though. =
Bob Dunahugh ________________________________ From: Bob Dunahugh =
Sent: Tuesday, January 2, 2018 5:08 PM To: gmcli=
st Subject: RE: The stock temp gauge doesn't really tell =
you your operating temps. Why that's a problem Mike K. Thanks. I t=
hink this is more of a problem then is generally thought. I pull higher GVW=
's more then most. And never had any add on items installed on our 403 GMC.=
Radiator inspections on attendees GMC's. Might make for a good tech sessi=
on at the GMCMI rally in Tucson. Line them up, and start checking with my i=
nspection camera. Drain pan, funnel, and the camera. At a cost of FREE. Go=
od idea, or not. Any input out there? Bob Dunahugh Ou=
r first 78 Royale came with a Digi panel. I knew my engine temps under all =
conditions. Then the fire. Bought another 78 Royale. But the Digi panel was=
n't being made at that time. Both GMC stock temp gauges read the same. But=
it didn't take long before I had a feeling that this second Royale was run=
ning hotter. No boil overs. Just didn't feel right. So on our next trip. I =
raise the engine cover several times to check the engine temp sender with =
an inferred temp reader. Found that this Royale was generally operating ab=
out 10 degrees hotter with the stock gauge reading in the normal range as =
compared to our first GMC. Jim at Applied GMC had started producing the Dig=
i panel. And had them at the GMCMI rally that we were going too. Installed =
the Digi panel at the rally. On the way home the panel also confirmed what=
I thought. So why the running hotter? Checked the thermostat. It was a goo=
d operating 180. But I changed to a proper 195. Fan clutch? Maybe. Well J=
im K at Applied started selling a fan clutch that is controlled by engine b=
lock sensors. I liked the idea that this system is more proactive in contro=
lling engine heat buildup. Plus I can turn the clutch on for the fan by a d=
ash mounted switch when I want. So I bought that fan clutch at the GMCMI ra=
lly. I had recently put on an aluminum 307 Olds intake manifold. So I knew=
the engine was clean inside. Did the engine have a car water pump? Don't k=
now. But even if there's a car pump. That's not the real big problem. Next =
I drained the radiator. Put my inspection camera in the radiator. Radiator=
's my problem. Looked heavily corroded at the crossover tubes. Going to put=
the radiator from the burned GMC in soon. Probably check/change water pump=
anyway while I'm doing other work in that area. Installing more gauges to =
look at isn't the best idea in my opinion. One. I want to be looking at th=
e road for safe driving. Two. The Digi panel has gages. But it's audible a=
larm is your best engine/trans protection. Bob Dunahugh 78 Royale
