Coolant flow direction in hoses

[Dennis Nicholls]

The coolant hoses in my car are original, as evidenced by the factory cosmoline overspray on them. Presently only the "green arrow" hose on the Pelican photo looks to be getting droopy and bulging.

http://www.pelicanparts.com/techarticles/Boxster_Tech/29-WATER-Flush/images_large/Pic2.jpg

According to the flow diagram on page 19-2 of the Bentley manual, that's actually the hot coolant outlet from the engine going forward to the radiators. It would make sense it's the first hose to go bad as it's large (therefore heavy) and carries the hottest coolant. But this would make the "orange arrow" hose, connected at the thermostat, the return hose that carries warm coolant back from the radiators. Wouldn't this make the thermostat close down, thus making the cooling system not functional? :huh:

I found this simplified cooling system diagram searching on line.

http://www.bombaydigital.com/boxster/projects/radiator/photos/coolant_flow.png

If this is correct there's some kind of "side door" to the thermostat that lets hot coolant in directly from the engine. Is this how it works?

Edited March 21, 2014 by Dennis Nicholls

[JFP in PA]

The purpose of the thermostat is to stop or reduce coolant flow until a set temperature is reached in the engine.

[Dennis Nicholls]

^{It's just that on other cars I've worked on the thermostat housing is for a hot water outlet, not a cooler water inlet.}

^{But the green arrow hose is the outlet, right?}

Edited March 21, 2014 by Dennis Nicholls

[JFP in PA]

^{It's just that on other cars I've worked on the thermostat housing is for a hot water outlet, not a cooler water inlet.}

^{But the green arrow hose is the outlet, right?}

Yes.

[Dennis Nicholls]

Thanks. I've got the green, orange, red, and purple arrow hoses on order - might as well change them all since most of the labor is refilling and "burping" the cooling system.

[JFP in PA]

Thanks. I've got the green, orange, red, and purple arrow hoses on order - might as well change them all since most of the labor is refilling and "burping" the cooling system.

Why not invest in the Uview airlift system and refill it with no chance of air entrapment in about 5 min.?

[mckinlay]

2+ on the Uview airlift system. It's not that expensive, You can use it on almost any car. It greatly simplifies refilling your cooling system. It borders on the impossible to get all the

trapped air out by "burping". Yes it can be done, but it can take days. Since I bought mine, it seems I have had to do something that involves draining coolant several times and it

has more than paid for it's self. You won't believe how easy it is to use. One point though, you need to have an air compressor with sufficient CFM to operate it efficiently.

[Dennis Nicholls]

How can the UVIew Airlift be any good if Harbor Freight doesn't sell a cheap knock-off copy?

[JFP in PA]

How can the UVIew Airlift be any good if Harbor Freight doesn't sell a cheap knock-off copy?

Patented design.

[Dennis Nicholls]

Sorry I was making a joke.

I looked up patents with UView as assignee. They got a few, named inventor Thomas Klamm. Base patent 6,152,193 issued 28 Nov. 2000 with apparatus claims. There's a continuation with method claims and a CIP too.

Cheapest I've found for UView 550000 is $110 shipped at ToolTopia.

Edited March 22, 2014 by Dennis Nicholls

[JFP in PA]

Sorry I was making a joke.

I looked up patents with UView as assignee. They got a few, named inventor Thomas Klamm. Base patent 6,152,193 issued 28 Nov. 2000 with apparatus claims. There's a continuation with method claims and a CIP too.

Cheapest I've found for UView 550000 is $110 shipped at ToolTopia.

Try the RennTech store Amazon, they appear from time to time around $100, with free shipping.

[Dennis Nicholls]

Pedro has a tutorial for using the UView Airlift to fill a 986 Boxster.

http://www.pedrosgarage.com/Site_3/Flush_Coolant_System.html

As you pointed out in another forum, the Airlift sucks out the air but not the coolant. I presume this is because air is a compressible fluid whereas coolant is an incompressible fluid.

My trusty Sanborn compressor puts out 4.2 SCFM at 90 psi which ought to be enough.

[JFP in PA]

Pedro has a tutorial for using the UView Airlift to fill a 986 Boxster.

http://www.pedrosgarage.com/Site_3/Flush_Coolant_System.html

As you pointed out in another forum, the Airlift sucks out the air but not the coolant. I presume this is because air is a compressible fluid whereas coolant is an incompressible fluid.

My trusty Sanborn compressor puts out 4.2 SCFM at 90 psi which ought to be enough.

Actually, when the Uview unit pulls 25-26 inches of vacuum, at that point there simply is no air left in the system. After testing the system for leaks by watching the vacuum level for several min., the vacuum in the system pulls the liquid coolant in until there is no more vacuum, and the system is full of coolant.

[Dennis Nicholls]

I just ordered a 550000 for $92 shipped - Amazon warehouse deal, "open box" type deal.

Edited March 22, 2014 by Dennis Nicholls

[2000GotBoxS]

Hey Guys,

Dennis & JFP especially, I am wondering if your diagrams are actually backwards. The only reason that I am curious is because I just had my water pump impeller explode into a million little pieces with no warning, and immediately. I was driving about 95mph, and the coolant level light started beeping and of course the alternator light, and the ABS light, the power steering light, everything went out as the bearing shattered and the belt shredded.

Well, the plastic impeller, now being in a million little pieces, is in my coolant. Little plastic fragments and "hopefully" not the little ball bearings and the stick bearings, that make up the water pump, are all over the coolant stream.

I am wanting to run water through the system backwards and see if I can recover all of the fragments. I've basically been putting the pieces back together to try and assemble it on a bench and see how much is remaining.

So, according to the Pelican Parts picture that you posted, THEY say that the green arrow is the RETURN HOSE FROM RADIATORS, and that the orange hose is SUPPLYING WATER TO THE RADIATORS. You say the opposite.

Does anyone know for sure? I want to make sure I flow the water backwards, and not forwards thru all of the components.

Thanks

[JFP in PA]

Hey Guys,

Dennis & JFP especially, I am wondering if your diagrams are actually backwards. The only reason that I am curious is because I just had my water pump impeller explode into a million little pieces with no warning, and immediately. I was driving about 95mph, and the coolant level light started beeping and of course the alternator light, and the ABS light, the power steering light, everything went out as the bearing shattered and the belt shredded.

Well, the plastic impeller, now being in a million little pieces, is in my coolant. Little plastic fragments and "hopefully" not the little ball bearings and the stick bearings, that make up the water pump, are all over the coolant stream.

I am wanting to run water through the system backwards and see if I can recover all of the fragments. I've basically been putting the pieces back together to try and assemble it on a bench and see how much is remaining.

So, according to the Pelican Parts picture that you posted, THEY say that the green arrow is the RETURN HOSE FROM RADIATORS, and that the orange hose is SUPPLYING WATER TO THE RADIATORS. You say the opposite.

Does anyone know for sure? I want to make sure I flow the water backwards, and not forwards thru all of the components.

Thanks

The diagrams are correct, the line that goes into the thermostat housing (orange in the photo) is the return coming back from the radiator's to the engine, and Pelican has been wrong before.

[2000GotBoxS]

hahaha, I am actually on the phone with them right now ordering a motor mount to replace while I am under there.

So, in order to flow the water backwards, where should I shove the hose? I suspect at this point, that the only thing inside the engine is just small bits of floating plastic, as I have managed to get most of the parts assembled together on the bench, and most is there, but, what terrifies me, is the possibility of the metal bearing balls being inside the engine. I will flush the radiators, and the heater core is even easier, but, I am worried about the engine itself containing these pieces. Look at these photos..... I've never seen anything completely fall apart so quickly and not give ANY warning. The car NEVER overheated, because as soon as the light started flashing, I coasted off the freeway and into a gas station and got the tow ride of 50 miles back home.

I want to post a couple of pictures on here of what I have actually fished out already, but, I don't know how to. Which opening do you think is best to put my hose to flush out any debris?

Thanks,

B

[JFP in PA]

hahaha, I am actually on the phone with them right now ordering a motor mount to replace while I am under there.

So, in order to flow the water backwards, where should I shove the hose? I suspect at this point, that the only thing inside the engine is just small bits of floating plastic, as I have managed to get most of the parts assembled together on the bench, and most is there, but, what terrifies me, is the possibility of the metal bearing balls being inside the engine. I will flush the radiators, and the heater core is even easier, but, I am worried about the engine itself containing these pieces. Look at these photos..... I've never seen anything completely fall apart so quickly and not give ANY warning. The car NEVER overheated, because as soon as the light started flashing, I coasted off the freeway and into a gas station and got the tow ride of 50 miles back home.

I want to post a couple of pictures on here of what I have actually fished out already, but, I don't know how to. Which opening do you think is best to put my hose to flush out any debris?

Thanks,

B

Welcome to the wonderful world of composite water pump impellers.............

If you forced water into the hose where it connects to the thermostat housing, you would be flowing water backwards into the radiators. If you removed the thermostat housing (to prevent the stat from blocking flow) and then pushed water into where the other hose connects to the engine, the water would be flowing backwards through the engine.

[2000GotBoxS]

Thank you so much JFP. I appreciate your help. Just one more clarification. I have removed all of the hoses from the engine in order to separate them from the system, and clean out each components separately. I have the 3 rads and the heater core isolated and can handle them. I have removed the thermostat housing and if I understand this correctly, I can insert the hose into the hole in the engine that is under the thermostat housing and therby achieve water flow in reverse of normal.

Is that what you are saying? Oh, and the water pump is not reconnected yet either. I did however find a very nice metal impeller replacement.

JFP, I really appreciate your help.

Thanks.

[Dennis Nicholls]

In the meantime I've found another Airlift demo video for Boxsters.

http://www.youtube.com/watch?v=FQnfUe6P5VI

[2000GotBoxS]

Does anyone have a diagram or schematic of the 3.2L Boxster engine's water flow thru the engine itself? I haven't been able to find anything online that shows the flow pattern inside the engine .

What a mess, I'm telling you. I've never taken apart one of these engines, so, I haven't the foggiest as to how it all moves thru the engine itself. JFP, you are helping immensely, as this has helped me to get almost all of it down.

Thanks again,

B

[Loren]

Cooling System (Boxster/Boxster S)

(click to enlarge)

[JFP in PA]

Thank you so much JFP. I appreciate your help. Just one more clarification. I have removed all of the hoses from the engine in order to separate them from the system, and clean out each components separately. I have the 3 rads and the heater core isolated and can handle them. I have removed the thermostat housing and if I understand this correctly, I can insert the hose into the hole in the engine that is under the thermostat housing and therby achieve water flow in reverse of normal.

Is that what you are saying? Oh, and the water pump is not reconnected yet either. I did however find a very nice metal impeller replacement.

JFP, I really appreciate your help.

Thanks.

First of all, DO NOT use a metal impeller pump in these cars. The composite impeller is there for a reason; when these pumps begin to wear, and they all do, the shaft is going to wobble a bit. When that happens with a metal impeller pump, the impeller starts machining away the back of the pump cavity, which happens to be the alloy engine cases. You can quickly do irreparable damage to the cases. Even engines that only suffered slight metal impeller damage were observed to have reduced coolant flow due to the now larger gap between a new pump's impeller and the damaged cases. Do not use metal.

A good idea for your flush is to get some appropriate sized large rubber stoppers and slip on hose fittings that you can use to jury-rig a more water tight seal for the hose in the openings while back flushing. Makes the process quicker and a lot less messy.

[2000GotBoxS]

Thank you so much JFP. I appreciate your help. Just one more clarification. I have removed all of the hoses from the engine in order to separate them from the system, and clean out each components separately. I have the 3 rads and the heater core isolated and can handle them. I have removed the thermostat housing and if I understand this correctly, I can insert the hose into the hole in the engine that is under the thermostat housing and therby achieve water flow in reverse of normal.

Is that what you are saying? Oh, and the water pump is not reconnected yet either. I did however find a very nice metal impeller replacement.

JFP, I really appreciate your help.

Thanks.

First of all, DO NOT use a metal impeller pump in these cars. The composite impeller is there for a reason; when these pumps begin to wear, and they all do, the shaft is going to wobble a bit. When that happens with a metal impeller pump, the impeller starts machining away the back of the pump cavity, which happens to be the alloy engine cases. You can quickly do irreparable damage to the cases. Even engines that only suffered slight metal impeller damage were observed to have reduced coolant flow due to the now larger gap between a new pump's impeller and the damaged cases. Do not use metal.

A good idea for your flush is to get some appropriate sized large rubber stoppers and slip on hose fittings that you can use to jury-rig a more water tight seal for the hose in the openings while back flushing. Makes the process quicker and a lot less messy.

THANKS SO MUCH LOREN, & JFP This will help me immensely. There is little plastic pieces all over, but, I am most concerned with the half of the ball and stick bearings that are missing. I found all of the metal pieces in the plastic covers on the bottom of the car, but, I found the bearing retainer inside the thermostat housing, and the thermostat had closed down on it, if those **** little pieces of metal went inside the coolant and not outside onto the freeway, I sure want to get them all removed from the system. So far I haven't found anything other than the plastic in the inside the coolant stream. At least I now can figure out which ways to apply water pressure to back flow the system, and remove all the doubt I have right now with buttoning everything up.

[Dennis Nicholls]

I've discovered a source for my confusion in the original post. It's in Dempsey's book "101 Projects...Boxster" on page 117, in the notes for Fig. 2. There he states the "green arrow" hose is the RETURN hose from the radiators. If you have this book you may wish to pencil in a correction.