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heater core coolant flow

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13K views 7 replies 5 participants last post by  85K1062  
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#1 · (Edited)
Anyone know for sure which heater core hose is the supply line and which is the return line on an LBZ?

There are two lines at the firewall:
1) a short "S" shapped one that comes from the firewall and connects to the EGR cooler just below (this hose is on the right as you face towards the engine compartment and may be no more than 12" long?)
2) a very long hose that comes from the firewall and heads down under all the front plumbing (it is on the left as you face the engine compartment, but I cannot see the point of connection of the line down below)


I see two possible scenarios for coolant flow to/from the heater core:
a) GM is using the heater core to extract heat from the coolant, and then sending the "cooled" fluid to the EGR cooler to regain heat (assisting in cooling the exhaust for engine consumption), or ...
b) GM is using the EGR heat exchanger to further heat the coolant, and then sending it to the heater core to have a nice hot medium


I'm leaning towards "a", but I'm not convinced I'm correct. So which is it?
 
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#2 ·
Sorry, I do not have an egr, truck gets warm in the winter, thats all I care about. charlie
 
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#3 · (Edited)
For the record, I discovered it.

Coolant flows from the EGR cooler to the heater core. Installed my new coolant bypass filter.
 
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#4 ·
How much was the coolant bypass filter? Who's system was it?
 
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#5 ·
My coolant bypass filter setup was less than $50. I purchased the Filter, Head, brass tee's, 90's and hoses from Napa. Cut drilled and painted a piece of 4" angle iron for the mount.
Pics in garage.
 
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#6 · (Edited)
I got mine from nasautomotive.com and I got the "universal" kit for 5/8" hoses. Fits perfect. Plus, the filter head is made of aluminum; no rust! Top flight kit! I looked into making one of my own, but it was a LOT easier (and only a few dollars more) to get the one form the above supplier. $92 shipped to my door. http://www.nasautomotive.com/Universal_Kits_s/34.htm


I'd be curious how anyone could make the whole system for "less than $50" from Napa, considering the mount alone retails for $52. The filter is $15, and then you have to get all the hoses, clamps, fittings, etc. I find it hard to believe anyone made a system buying all the stuff for less than $50. Not today, anyway. Perhaps 15 years ago for that price, but not today, from Napa. Plus, the Napa base is steel, and the nasautomotive part is alumimum.

Here's how it breaks down for Napa:
filter base #4019 is $52
filter #4070 is $15
2 tee's: $10
6' of hose: $8
8 s/s clamps: $5
2 hose barbs: $7
2 mini-valves: $20
Total: $117 from Napa.

Fleetfilter has better prices based upon bulk Napa parts: www.fleetfilter.com


You can shave off a bit of money by going to fleetfilter.com and getting the filter base and filters 1/2 price, but STILL going to be around $85, and you still have to source other stuff and include your fuel driving around. I did find some decent mini valves at Grainger. But each time you source from a differnt place, you have to pay shipping from each source.

Or, get it delivered from nasautomotive.com to your door with all top quality fittings (a complete kit with nothing missing) to your door for $92 INCLUDING SHIPPING.

A no brainer ...
 
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