There was a good post, I read at one time on cleaning up the engine compartment...I am looking for the post on how to redo the heater hoses on the LO3....Am looking to move, or remove the vacumn unit...Can someone lead me to the post???? I have searched, but guess im not using the right words......Thanks, Tom

Need the same thing. i also have an LO3 and I just bought some Hi-Miler hoses and need to install them. But want to know the routing for all hoses and how to route without the smog and heater diverter valve. Cant wait, all new hoses, clamps, ignition, intake, exhaust, valve covers, tubing, wire loom, water pump...cant wait to put all this shyt on in one swoop. Nice clean engine bay.

Anyone????? I cant find that post for nothing...I want my heater on my LO3 to work, but I want to get rid of the vacumn thing, if I can..Also want to get rid of some of the heater hoses toward the front, and move them back out of the way.....Tom

Not sure what post you mean, but I did this on my car.
I bought the correct non AC metal pipe from GM, which runs along the frame rail. The AC pipe with the heater valve has the "T" in it which you no longer need.

Here's what it looks like afterwards.
For the intake to heater core hose I just went to the parts store and got a 90* bend heater hose right diameter 3' in length in the and cut to fit.
The metal pipe to the oil cooler pipe is stock, same for the cooler to radiator. With no oil cooler it just runs a hose from the the frame rail pipe to the radiator.

Here's a pic of the new pipe. Not sure if you can still get them. I bought mine in 2004.


OK just looked at my 90 service manual. Things are different on the LO3.
part number - 14089307 ( pipe pictured above.. this is the same for TPI and TBI or carb )
the replacement hose part number is - 10068140 ( this one is the short one on top.. goes from back of intake manifold to the heater core )
the rest of the hoses from the heater core to the pipe and pipe to radiator are the same as what are already on your car.




Here are some pics of with AC and with out. Should be able to buy the hoses at the parts store.

The vacuum switch routes hot water from the intake,
either through the heater, or straight into the radiator.
This hot-water tap at the back of the engine is one of
GM's better ideas, getting the coolant flowing more
evenly through the engine. Taking it out for the sake
of engine bay cleanliness doesn't make sense to me.
And if you remove the vacuum switch, and re-route water
to the heater, then it will be hot all the time, which in
our climate, also doesn't make sense to me. That being
said, I intend to tuck mine away in a less obtrusive location,
by using just hoses, and some PVC tee's.

<~~~Still need to know routing of all hoses. I have the hi-miler hoses and just removed my Heater Diverter valve Smog box and pump and AIR system...Need to know where to route these hoses now without all that stuff. Thanks.

P.S. The only one I see and know is the intake manifold that goes from the firewall straight to the manifold....as it did when the smog and valve were hooked up. As for the other heater hose....? I think it just goes to the radiator?

Hell, I do alot of things that dont make sense.....BTW, I got you your rely, and wiring for it, got about 9 inches of wire with it..Come by and get it when you can.......For the record, I dont want to make it hot all the time, I just want to move the stuff out of the way....My last thirdgen used a different system without the vacum valve....Tom

Ok.. I looked through my parts catalog and the 87 LG4 setup uses a bypass valve so it won't be hot all the time, but it is located right next to the firewall. It only has 1 inlet, and 1 outlet not a second outlet. So it doesn't really by pass but just shut the flow off. The other line seems to have a "U" shaped loop to it.
If that is more what you are looking for I could post the diagram of that setup.

That is what I think im looking for......I beleive my last 86 was like that.....What I want to do is at the very least shorten the hoses, and mount it on the firewall where the AC box used to be.....Will look so much cleaner...Traveler has convinced me to keep the coolant flow thru the manifold to keep the heads a bit cooler, so Iwill probably just tuck it all away...I would like to see that diagram tho, if you would post it....Thanks very much, Tom

do you remember where you got the pipe without the t in it from

this post is more than 2 years old ??? good luck .

thanks uncle tom your a real help