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Old 11-22-2021, 10:23 PM   #1
67swb72klb
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2001 slow to heat

My 2001 RCSB with the 5.3 just does not build heat fast in the colder months even if its just in the 40s let alone when we get to the sub zero temps that are around the corner.
Takes forever to get up to just under the 210 mark
Replaced the T stat once and the water pump got replaced when it started leaking neither one made any difference

Any ideas?
Thanks!
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Old 11-23-2021, 12:27 PM   #2
hatzie
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Re: 2001 slow to heat

Are you sure the thermostat is the correct temp and it's opening when it's supposed to?

Do you have an air pocket in the cooling system or low coolant level?

Are you getting heat or is the heater blowing colder than it should with the engine warmed up?
I've had heater cores rot out internally between the intake and outflow ports on 1978 Dodge W200 Power Wagon and one of my mid 80's Subaru Brats. There's a separator panel in some heater cores to force the coolant to flow through half of the heat exchanger and back through the other half that rotted through in those rigs. The coolant was almost completely bypassing the failed heat exchangers through the rusted out separator panel. A replacement heater core made them heat too well.

Last but not least is the temp gauge actually reflecting the real engine temp?
Failing Engine Coolant Temp senders can read lower than actual and react slowly to temp changes.
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1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
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RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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Old 11-24-2021, 09:00 PM   #3
67swb72klb
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Re: 2001 slow to heat

Thanks...
I put a standard thermostat in it about a year before the water pump started leaking and also played around with the coolant level without any change
The gauge is pretty much saying what the heater is putting out.
This truck has been like this since I bought it three years ago.
City driving this thing takes forever to get close to 210

It is a Ca. truck I guess they don't need much heat anyway..
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Old 11-25-2021, 10:57 AM   #4
hatzie
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Re: 2001 slow to heat

You can get 165, 180, & 195 thermostats.
I always specify the temperature. I've had the parts guys hand me 180 stats because they didn't have the 195
I believe the stock stat in the 2001 4.8/5.3L is 195.

Vacuum cooling system fillers are almost a must have tool anymore.
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
hatzie is offline   Reply With Quote
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