Hot Rod Roy

Since you can't figure out truth from fiction, you can answer your own question!
1. Look at your water pump.
2. Determine which direction the input shaft turns.
3. Verify that water would be forced by the impeller thru those two outlet ports into the front of the block.
4. If those two outlet ports in the water pump that connect to the block are the outlets, the large tube that connects to the bottom radiator hose must be the inlet to the water pump!
5. The fitting for the heater hose goes into the inlet to the pump.
6. Water in the heater hose MUST flow into the pump, since that is the inlet to the pump.
7. Water in the heater hose must be flowing FROM the heater core!
8. That heater hose connects to the TOP tube of your heater core, which most people** would call the outlet tube.
9. The bottom tube of your heater core should probably be considered** as the inlet tube.

** I use these words because you need to decide for yourself whether this is accurate information.

We are anxiously awaiting your rebuttal.

cdm747

I believe I suggested you do that in your other post.

Tom400CFI

Hot Rod Roy is sure...and he's right. Both in his original advice (which hose is what) and in his method for determining which hos is what. You could follow his advice and have a conclusion to this debacle, or keep asking for more "votes". Best of luck!

savewave

If your posts are missing from this thread, please review the rules on hostile posting/personal attacks and take the pissin' match offline.

Hot Rod Roy

There is an excellent diagram in my FSM (pg.1B-19) that identifies the heater core inlet and outlet, and shows the hose routing between the engine, water pump and the heater core. I'll bet your '88 FSM has a similar diagram that would be appropriate for your '88. Every Corvette owner with an ounce of mechanical ability needs the FSM for their car. You do have an FSM, don't you?

cdm747

In the 88 manual it is on page 1B-20. It does not show flow direction in that diagram but i think Hot Rod Roy has pretty clearly stated which hose is which. I "personally" don't think it would make much difference which line he puts the shutoff valve in. If there is no flow the heat transfer is going to be negligible. Use your radiator as an example, does it get very hot before the thermostat opens. It is the same principle.

mtwoolford

you neglect to mention the "third hole" where the water pump mounts to the block; this bypasses hot water directly from the block back into the suction side of the pump; good for cold starts in sub zero weather , but of doubtful performance use; most performance oriented builds block this passage or at least restrict it.

IHBD

This passage actually goes into a cyl head. The passage is necessary to establish flow when the thermostat AND heater valve is closed.

Another thing regarding "flow" that hasn't been mentioned. In order for the water pump to "pump" water, there must be a pressure-drop across the inlet and outlet of the pump. In an L98, the "restriction" that creates the pressure drop is the head gasket. Pressure above the gasket is lower than below the gasket. When evaluating whether a particular port or point in the cooling system is "high", "low", or "the same" compared to another port, ascertain it's position above or below the head gasket. The thermostat and radiator are another pressure-drop that establishes flow between the two heater ports.

Hot Rod Roy

The OP's question was: "Which way does the water flow thru my heater core". How does this statement fit into that scenario?

Your statement confuses me. If there were a 4" hose between the WP outlet and the inlet, water would flow like crazy!

Tom400CFI

Don't need a restriction to flow to happen. The pump's rotating, centrifugal impeller spinning creates your pressure differentials allowing the water pump to "pump" water

cardo0

That is correct. The cooling system needs back pressure behind the T-stat to prevent boiling/vapor pockets at hot spots. And you can find large fender washer like orifices on the vendor shelf for this.

Tom400CFI

Ahh Cardo...jumping in with the fiction agin.
1. ihatebarkingdogs wasn't talking about boiling or vapor pockets. He didn't type a single word or letter on the topic....so how are you "agreeing" with...that??
2. Ya don't need "back pressure" to manage air pockets. What you need is water velocity and turbulence and some pressure. Pressure does help and we get that from our radiator caps + then phenomena of "expansion" when the coolant heats up. There is your pressure.


Orifices are for managing coolant temps in a very...very crude way. Mostly they're for old timers love "lore" and listen to the weird voices in their heads.

Here is some good reading that you should try to digest. If you're in a big hurry, or have a short attention span, just read the LAST TWO PARAGRAHPS.




.

cardo0

Your wrong. And your not worth the effort to prove it. Backpressure from the T-stat and its substitutes keep the coolant system solid more so than the radiator cap by itself. Try using Smoky Y. and others instead of your imagination.

Tom400CFI

I guess Stewart is wrong then too; you'll have to let those engineers know that they're wrong, and that you're good 'ol idol "Smokey" knows better. Boy you're a sucker for old time LORE.

ddahlgren

Wow it seems hard to generate 34 posts over this. The pump inlet is where water goes in as is the heater hose connection right above it. Take a sketch of all the devices that have coolant in them and where they connect to the pump inlet and place an arrow for flow direction and aim it at the pump inlet. Everything else is an outlet.
Looking at my L98.
Bottom of radiator to pump inlet
heater core to pump inlet
Top of intake before thermostat to TB from TB to heater core to pump inlet
Oil cooler from block to oil cooler to pump inlet
Top of manifold through thermostat to radiator to pump inlet.
Did not take the pump off to see where the bypass in pump goes but suspect the to prevent the pump from cavitating if all outlets are closed.
If the pump can output more flow than the outlet of what it is supplying there will be pressure generated at the pump outlet though suspect very modest as clearances are pretty generous.
Restrictors are generally used in racing vehicles as some coolant pressure is useful and it eliminates a moving part, the thermostat.

cardo0

Your over 200 years late in your imagination discovery. Try some real sience. A guy named Burnolli proved static pressure increased when flow slowed in a system from any restriction. While the radiator cap may hold say 10psi the pressure in the block between the pump and the T-stat restriction could well be twice that. I have never measured it so I guessing on the amount but it does increase the static system pressure and raises the boiling point of the coolant.

Again I find myself having to teach the local troll here basic science. What a waste!

Tom400CFI

It certainly IS a waste. Poor Cardo.... Reading comprehension continues to evade you.

Where did I contest that "static pressure increased when flow slowed in a system"? Hmmm? Cardo....I ask you; please quote where I contested that fact, would you?...so that I can hurry and correct that mistake. Would you please point that out for me? Thanks.

Also, recognize that I never mentioned "Burnolli" [sic] at all. Also notice that I actually said: ....so I'm not sure what you think that you're "teaching" here. Did you bother to read the link that I provided? If you did, were you able to comprehend it? You might try going back and re-reading...both what I actually typed in my threads and what is in the link.

FYI, you can get radiator caps over 20 lbs, and as I pointed out earlier, flow and turbulence help with air pockets more than pressure.

Today's assignment, Cardo, is to work on your reading comprehension and accuracy. Please post back when you've shown an improvement in those areas.

cardo0

Again your wrong. While adequate flow and turbulence is necessary the sbc has to much flow between the bores of the block and installing restrictor plugs in the deck is a normal modification for performance blocks. Reducing the flow rate and increasing backpressure. You could know this if you tried to read more than run your mouth. Smokey Y. (RIP) is a good place to start. And Smokey goes into great detail on the cooling system and modifications but his hard earned "Power Secrets" would be a waste on your imagination engineering through gossip.

Go ahead and run a higher pressure rad cap than your coolant system is rated for. Im sure you'll enjoy the new leaks created.

Tom400CFI

Cardo....you sure struggle with comprehension. I'm sorry for you. You can't decipher what I've written on these pages -yet you know about my reading history? Just keep saying that I'm wrong... and hoping that makes you right. Best of luck with that.

As you were Cardo.

cardo0

Your unmeasurable claims of flow & turbulence vs pressure will live on w/o you. Your undefinable stories of Stewart engineers reporting something that should support your imaginations will continue as forum legend. And your suggestion to install 20lb caps on a 15lb rated system will be seriously missed.

Bye bye!