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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: DirtyLittleSecret on May 26, 2008, 12:22:38 am
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So, my distributor finally gave out (258k miles on it). Already had an Edelbrock EPS manifold with all the trimmings sitting in the garage, and finally said fooey to the disgraced cast iron monster. Went and got a new Accel distributor, Accel coil, some chrome, and some 8.8mm MSD wires. Replaced the heater core as well (it broke when replacing all the hoses/belts), and tossed in a new 180* high flow thermostat. Went out today to test-drive and set the timing "by ear", and got it just about perfect. WOT and no oddities, and no leaks.
Here's the problem: now it runs WAY cold. Setting the heater to hot gets me luke-warm air, and cold is just cold. Temp shows it pretty cold as well (as if it ever really got hot to begin with). Do I need to step up to a 195* thermostat? I've worked on 350's before, but not in these K20's with ginormous radiators/etc...maybe I'm just too tired, but if you've got some additional ideas it'd be great.
Next up...Ramshead headers, Summit ignition box, and some air bags for towing. Oh, and an empty wallet.
BTW: Wishin' you all a rewarding Memorial Day.
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the stock T-stat was a 195°
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195* huh. Wow, I wouldnt have thought it! Thanks.
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I'd go stock too. 195 degree.
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Problem solved with a new 195 Mr Gasket High Flow thermostat. Even got a new water pump tossed on (free), and acid flushed the system.
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OKAY. PROBLEM NOT SOLVED :(. Went for a 75 mile drive tonight, and had to wear a jacket since the bloody heater was luke-warm. Top radiator hose is getting warm, but not hot (can hold my hand on it).
Any other ideas? This isnt rocket science, but am kinda confused as to what I'm missing here. Could I really have had two failed t-stats?
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Whats the guage reading at?? Maybe your heater core is clogged. Maybe the exterior ventilation is suck open. Maybe the vacume isn't routed correctly to the switch. How are your heater hoses routed?
Your cab should be like a sauna.
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Whats the guage reading at?? Maybe your heater core is clogged. Maybe the exterior ventilation is suck open. Maybe the vacume isn't routed correctly to the switch. How are your heater hoses routed?
Your cab should be like a sauna.
Gauge is barely getting above the bottom mark (original gauge, and currently have two temp sensors, and both give the same reading). Just installed a new heater core while I was in there, and it flowed fine when I tested it. Prior to installation it had no issues, but was never a sauna to begin with but would definitely produce heat. I'll check the vents, but there is no breeze, and I can tell when the vents are open. Vacume to the switch? To my knowledge, this is a mechanical system and didnt change any vac lines. Heater hoses are routed the same as before, and really cannot make a mistake there since the two are different sizes. They can only fit one way. I'm actually kinda dumbfounded.
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Here's how you fix your problem. Remove that brand new thermostat and install it in the garbage can. Install a Stant superstat in its place.
I had the very same problem with a "high-flow" thermostat I bought at the same time I ordered a new Stewart stage 1 water pump. These stats are only necessary for pumps that do not have a bypass passage built into the pump housing (that second small hole on the passenger side of the block). They are simply a Robertshaw thermostat with holes drilled in them so some coolant is always bypassing them. Not a good idea for an ordinary street vehicle. I replaced a perfectly good coolant sensor before discovering this. Good luck.