Help, '87 454 runs too hot - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Joesjunk** · 07-16-2016, 02:08 PM

Looking for some advice on why my bone stock, 101k mile 1987 V/30 truck wants to run hot. I have been over everything, even had head gaskets changed ( although it didn't appear to need them). It seems to stay cool just sitting running, even with the ac on. But gets warmer on the road. It never over heats, but gets hotter than it should. It has a 180 thermostat, and the gauge is working correctly. It will sometimes get up to the next mark on the gauge. Any indepth advice?

Matt Man · 07-16-2016, 02:38 PM

How is the fan clutch, it has one I'm assuming? Mine did the same thing, replaced the fan with a 6 blade instead of 3 and a heavy duty fan clutch for the so cal desert climate.

*gmachinz* · 07-16-2016, 02:43 PM

If your temp sender is in the head, I'd say it's normal. The head will read 15-20 degrees warmer than the intake which is the usual spot. Not to mention the gauge could be off as much as 3-4 degrees too.

71swb4x4 · 07-16-2016, 03:35 PM

Quote:

Originally Posted by gmachinz

If your temp sender is in the head, I'd say it's normal. The head will read 15-20 degrees warmer than the intake which is the usual spot. Not to mention the gauge could be off as much as 3-4 degrees too.

I agree, I don't think it's too hot.

*gmachinz* · 07-16-2016, 03:41 PM

If it IS bone stock, it couldn't hurt to replace the water pump....otherwise, just for giggles can you swap th sender to an intake passage to see what the difference is on the gauge? If it's a noticeable difference, I wouldn't worry about it running too warm.

tucsonjwt · 07-16-2016, 04:37 PM

Did you use an infrared thermometer on the engine? This would be a way to check on the accuracy of the gauge. I had an over temp condition on my 02 Cavalier when driving at highway speed and it was a clogged radiator. When I replaced the radiator all was well. Replacement radiator was just an Autozone plastic/aluminum one.

My 83 C20 454 never gets much above 180, but it has a factory oil cooler and an auxiliary fan in front of the stock radiator. Of course, it is a Qjet, not TBI like yours. I did replace the fan clutch and water pump with AC Delco ones several years back. My engine is stock with all smog equipment intact.

AntiGov · 07-16-2016, 04:47 PM

Does yours have the odd looking factory auxiliary fan ? My 88 454 crew does. There were two for sale in the parts forum recently. I know you want to keep it all stock and these are factory.

**Joesjunk** · 07-16-2016, 06:21 PM

I have tried most of what you guys are saying. It has a new GM clutch on the fan. It is 100% bone stock except for dual exhaust and no converter. I even put a mechanical gauge in the other head and it reads the same as the factory gauge. I have the factory oil cooler and the aux fan in front of the radiator. I have a new GM radiator I am going to swap in it tomorrow and see what happens.
I also have an identical truck, only an '86 with a carb and it never runs above 190

Thanks for the replays. I'll let you know how the different radiator works

tucsonjwt · 07-17-2016, 09:35 AM

I think a power flush would be a good idea when you install the new radiator. I think that radiator will do the trick. Good luck.

*gmachinz* · 07-17-2016, 09:49 AM

Quote:

Originally Posted by Joesjunk

I have tried most of what you guys are saying. It has a new GM clutch on the fan. It is 100% bone stock except for dual exhaust and no converter. I even put a mechanical gauge in the other head and it reads the same as the factory gauge. I have the factory oil cooler and the aux fan in front of the radiator. I have a new GM radiator I am going to swap in it tomorrow and see what happens.
I also have an identical truck, only an '86 with a carb and it never runs above 190

Thanks for the replays. I'll let you know how the different radiator works

Wow....I'm not surprised you have a NEW GM radiator in your collection of parts-but man those are rare to find!! You can't get an actual BB spec radiator at parts stores anymore-they all try to sell a 3-core. NOS Harrison BB radiators gotta be tuff to find!!

Dead Parrot · 07-17-2016, 10:59 AM

Before you worry too much, verify the temp with an outside source. IIRC, the temp rating on a thermostat is the start to open temp. So your 180 is just starting to open at 180. It will take to 190~195 for it to be fully open. Now if your gauge is just 5% off, you could have a reading of 205 by the time your thermostat is fully open. If your gauge is 10% off, the reading could be 210~215. This assumes the sender is perfect. If sender is also 5 or 10% off and especially if it is off in the same direction as the gauge, your reading could well be 210~220 even if the actual engine temp is proper for your thermostat.

Also, double check the cluster contacts for corrosion and clean up the cluster grounds. Assuming it is original, your electrical stuff is 29 years old and it doesn't always age well.

Might try an aftermarket temp gauge and sender and see if it responds the same.

S10Fan · 07-17-2016, 11:49 AM

Infrared thermometer is a good investment for car guys. I fought a heating issue with a V-8 S-10, later found the gauge was way off. I had been using Sun gauges, called Sun and a tech guy told me their gauges had a 20% tolerance. Yeah, 20%!!

I realize yours is a factory gauge, just make sure it really is hot before fixing a motor that isn't broken.

**Joesjunk** · 07-17-2016, 01:48 PM

I have used the infrared thermometer on it and put a mechanical gauge on it. It is running hot. I swapped the radiator just now and just waiting on a new upper radiator hose to come in from the auto parts store in a few hours. Ill test it out this afternoon and give an update

Thanks again for the replies

**Joesjunk** · 07-17-2016, 05:57 PM

Well I swapped the radiator out of my '86 K/30 into the '87 and so far that seemed to have fixed my problem. So now my NOS radiator will go in my '86 K/30.
I even had a radiator shop look at my old radiator over a year ago and they thought it looked ok. Guess not lol

HOTFUN · 07-17-2016, 09:23 PM

I would have bet the fan clutch first as I have seen that more often than any other cooling at speed issue but one more check is the radiator cap. It has to be 15 lbs to pressurize the crossflow design radiator and if the spring is weak or gasket tore it will not circulate the coolant properly. Just a thought if the radiator shop said the radiator had pressure checked fine before.

**Joesjunk** · 07-17-2016, 09:45 PM

Quote:

Originally Posted by HOTFUN

I would have bet the fan clutch first as I have seen that more often than any other cooling at speed issue but one more check is the radiator cap. It has to be 15 lbs to pressurize the crossflow design radiator and if the spring is weak or gasket tore it will not circulate the coolant properly. Just a thought if the radiator shop said the radiator had pressure checked fine before.

Mark, they just looked at it, didn't do a test on it. It has a new GM cap on it too.

SparkyRnD · 07-23-2016, 05:15 PM

We also make radiators here in the USA using domestically sourced materials by hand to fit your truck (and we can put the inlet / outlet wherever you need at no additional charge). They are all tig welded, no epoxy or glue either. Plus, we are a site sponsor. Let me know if you are interested.

**Joesjunk** · 07-23-2016, 08:13 PM

Quote:

Originally Posted by SparkyRnD

We also make radiators here in the USA using domestically sourced materials by hand to fit your truck (and we can put the inlet / outlet wherever you need at no additional charge). They are all tig welded, no epoxy or glue either. Plus, we are a site sponsor. Let me know if you are interested.

Thanks for the info. I did get the truck fixed and running just like it should.

SparkyRnD · 07-23-2016, 09:00 PM

Cool! (pun intended)

07-16-2016, 02:08 PM	#1
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,709	Help, '87 454 runs too hot Looking for some advice on why my bone stock, 101k mile 1987 V/30 truck wants to run hot. I have been over everything, even had head gaskets changed ( although it didn't appear to need them). It seems to stay cool just sitting running, even with the ac on. But gets warmer on the road. It never over heats, but gets hotter than it should. It has a 180 thermostat, and the gauge is working correctly. It will sometimes get up to the next mark on the gauge. Any indepth advice? Attached Images __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

07-16-2016, 02:38 PM	#2
Matt Man Registered User Join Date: Oct 2009 Location: Buhl, Idaho Posts: 1,438	Re: Help, '87 454 runs too hot How is the fan clutch, it has one I'm assuming? Mine did the same thing, replaced the fan with a 6 blade instead of 3 and a heavy duty fan clutch for the so cal desert climate. __________________ 86 c30 crew cab dually 454/400 4/6 drop SOLD 1-8-11 1981 chevy K10 short Bed Scottsdale SOLD 10-26-2020 67 GMC Stepside Straight six/3 on the tree "The Peach" 2020 Silverado Double Cab LT Z71 5.3 8 speed Daily Driver K10 build http://67-72chevytrucks.com/vboard/s...d.php?t=671934 The Peach build http://67-72chevytrucks.com/vboard/s...d.php?t=733903

07-16-2016, 02:43 PM	#3
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: Help, '87 454 runs too hot If your temp sender is in the head, I'd say it's normal. The head will read 15-20 degrees warmer than the intake which is the usual spot. Not to mention the gauge could be off as much as 3-4 degrees too.

07-16-2016, 03:41 PM	#5
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: Help, '87 454 runs too hot If it IS bone stock, it couldn't hurt to replace the water pump....otherwise, just for giggles can you swap th sender to an intake passage to see what the difference is on the gauge? If it's a noticeable difference, I wouldn't worry about it running too warm.

07-16-2016, 04:37 PM	#6
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Help, '87 454 runs too hot Did you use an infrared thermometer on the engine? This would be a way to check on the accuracy of the gauge. I had an over temp condition on my 02 Cavalier when driving at highway speed and it was a clogged radiator. When I replaced the radiator all was well. Replacement radiator was just an Autozone plastic/aluminum one. My 83 C20 454 never gets much above 180, but it has a factory oil cooler and an auxiliary fan in front of the stock radiator. Of course, it is a Qjet, not TBI like yours. I did replace the fan clutch and water pump with AC Delco ones several years back. My engine is stock with all smog equipment intact.

07-16-2016, 04:47 PM	#7
AntiGov Registered User Join Date: Oct 2011 Location: central Oregon Posts: 1,225	Re: Help, '87 454 runs too hot Does yours have the odd looking factory auxiliary fan ? My 88 454 crew does. There were two for sale in the parts forum recently. I know you want to keep it all stock and these are factory. __________________ 88 3+3 454 400 205 410 drw to srw still in pieces 90 3+3 350 400 205 410 srw 84 1/2 ton lb 6.2 4x4 parts truck

07-16-2016, 06:21 PM	#8
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,709	Re: Help, '87 454 runs too hot I have tried most of what you guys are saying. It has a new GM clutch on the fan. It is 100% bone stock except for dual exhaust and no converter. I even put a mechanical gauge in the other head and it reads the same as the factory gauge. I have the factory oil cooler and the aux fan in front of the radiator. I have a new GM radiator I am going to swap in it tomorrow and see what happens. I also have an identical truck, only an '86 with a carb and it never runs above 190 Thanks for the replays. I'll let you know how the different radiator works __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

07-17-2016, 09:35 AM	#9
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: Help, '87 454 runs too hot I think a power flush would be a good idea when you install the new radiator. I think that radiator will do the trick. Good luck.

07-17-2016, 10:59 AM	#11
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,620	Re: Help, '87 454 runs too hot Before you worry too much, verify the temp with an outside source. IIRC, the temp rating on a thermostat is the start to open temp. So your 180 is just starting to open at 180. It will take to 190~195 for it to be fully open. Now if your gauge is just 5% off, you could have a reading of 205 by the time your thermostat is fully open. If your gauge is 10% off, the reading could be 210~215. This assumes the sender is perfect. If sender is also 5 or 10% off and especially if it is off in the same direction as the gauge, your reading could well be 210~220 even if the actual engine temp is proper for your thermostat. Also, double check the cluster contacts for corrosion and clean up the cluster grounds. Assuming it is original, your electrical stuff is 29 years old and it doesn't always age well. Might try an aftermarket temp gauge and sender and see if it responds the same.

07-17-2016, 11:49 AM	#12
S10Fan Old Heap Driver Join Date: Mar 2008 Location: Newport News, Va Posts: 2,642	Re: Help, '87 454 runs too hot Infrared thermometer is a good investment for car guys. I fought a heating issue with a V-8 S-10, later found the gauge was way off. I had been using Sun gauges, called Sun and a tech guy told me their gauges had a 20% tolerance. Yeah, 20%!! I realize yours is a factory gauge, just make sure it really is hot before fixing a motor that isn't broken. __________________ _____________________________ Bryan '99 Silverado 1500, 4.3, 5-speed, reg cab, short bed '50 Chevy 2DR Hard Top, 350/350, M2 Front End, 3:08 gear, cruiser. '40 F**d Sedan, all Chevy power, Heidt's front end, TCI rear, nice driver.

07-17-2016, 01:48 PM	#13
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,709	Re: Help, '87 454 runs too hot I have used the infrared thermometer on it and put a mechanical gauge on it. It is running hot. I swapped the radiator just now and just waiting on a new upper radiator hose to come in from the auto parts store in a few hours. Ill test it out this afternoon and give an update Thanks again for the replies __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

07-17-2016, 05:57 PM	#14
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,709	Re: Help, '87 454 runs too hot Well I swapped the radiator out of my '86 K/30 into the '87 and so far that seemed to have fixed my problem. So now my NOS radiator will go in my '86 K/30. I even had a radiator shop look at my old radiator over a year ago and they thought it looked ok. Guess not lol __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

07-17-2016, 09:23 PM	#15
HOTFUN Registered User Join Date: Jan 2001 Location: Lincoln, Nebraska Posts: 2,145	Re: Help, '87 454 runs too hot I would have bet the fan clutch first as I have seen that more often than any other cooling at speed issue but one more check is the radiator cap. It has to be 15 lbs to pressurize the crossflow design radiator and if the spring is weak or gasket tore it will not circulate the coolant properly. Just a thought if the radiator shop said the radiator had pressure checked fine before. __________________ '66 CST BBW swb fleet 327 fac ac '67 CST 4x4 swb 327 stepside project '72 Cheyenne K20 50k original '72 Cheyenne Super K20 project '73 Sierra swb 4x4 frame off in paint stage '74 Cheyenne Super swb w/16k actual '71 & 72 Cheyenne K10 4x4 swb's '70 426 HEMICUDA conv SHAKER 4 sp Dana 60 '60 Impala conv 327 PG fac ac loaded 3rd owner '72 GMC K2500 4x4 '59 Apache CST BBW fleetside swb 283 '73 ElCamino SS LS1 T56 true SS bucket tach '76 ElCamino SS 52k survivor '87 Grand National 41k True 2nd to last built in 1987. '86 K30 454 SRW fleetside CA since new '88 Trans Am GTA 39k bought new 2018 DEMON plum crazy @ 840HP! "Need for speed"

07-23-2016, 05:15 PM	#17
SparkyRnD Registered User Join Date: Dec 2011 Location: acworth georgia Posts: 890	Re: Help, '87 454 runs too hot We also make radiators here in the USA using domestically sourced materials by hand to fit your truck (and we can put the inlet / outlet wherever you need at no additional charge). They are all tig welded, no epoxy or glue either. Plus, we are a site sponsor. Let me know if you are interested. __________________ www.RnDFabrication.com Custom Radiators, Valve Covers and Overflow Tanks

07-23-2016, 09:00 PM	#19
SparkyRnD Registered User Join Date: Dec 2011 Location: acworth georgia Posts: 890	Re: Help, '87 454 runs too hot Cool! (pun intended) __________________ www.RnDFabrication.com Custom Radiators, Valve Covers and Overflow Tanks



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