Blew my coolant S hose (waterpump side)

[Jan Larsson]

Well not the best of days ... nice car show down south (1 1/2 h drive smaller roads and through one smaller city) ... so got it all prepared night before then drove down this morning.

Couple of red lights and smaller cues on the way down there when we got close then cues closer to the venue but nothing serious really ... however did notice the coolant temperature rising (scanmaster and temp gauge) the it did rise drastically into red ... 245 or so F ... and I lost all the coolant.

Stopped let it cool down as much as possible then on of with the engine until we could make it into an area to stop and properly look at it and the S-hose (bypass hose) at the waterpump end had popped off ...

Anyone had this happen? I suspect it leaked coolant and when I lost enough to raise the temperature the pressure built up shot the hose completely off and I had a nice (not) fountain emptying most of the coolant across the engine.

Looking at the waterpump nipple it's slightly coned and nothing to grab hold of the hose/clamp at all so can see it possibly shoot off (or slip off over time); anyone had problems with this and if so what was the cure (more than tightening the clamp as much as you can).

Will remove the radiator and flush the engine / radiator properly and reinstall the S-hose.

I hope I did not damage the engine due to it being possibly overheated ... oil and everything else looks good ... and we got the hose back on good enough to refill the coolant with water and drive back home and had no issues with temp rising more than what's normal when stood at red lights etc.

Anyway not the best of days and do hope nothing else happened to the engine (only got the 1500 miles since complete rebuild years ago).

 

[Nick Micale]

.....................Anyone had this happen? I suspect it leaked coolant and when I lost enough to raise the temperature the pressure built up shot the hose completely off and I had a nice (not) fountain emptying most of the coolant across the engine..................

You are most likely correct in your conclusion of how this happened.

My opinion is the clamp was not tight enough if the hose came loose, and I have seen the rare occasion that this hose has leaked because of that.

One cure is to drill a couple small by-pass holes in your thermostat, and eliminate this hose all together.

We do this often here in the desert, as many turbo cars do not even run a t'stat due to the brutal summer heat.

 

[Jan Larsson]

Thanks Nick, when I did the engine I used those constant tension clamps you see on all modern cars rather than the original style clamps ... so I think you are right not tight enough and eventually I lost it (the hose that is).

Is there a risk I damaged the engine if it did become too hot? If so what would be the signs to look for?

 

[earlbrown]

Keep an eye on your coolant level, check the inside of your valve cover (or breathers) for excess sweat, and normal signs of a blown head gasket or leaky intake manifold gasket.

 

[Pronto]

Last one I saw leak was from a blown headgasket.

 

[TurboSmart]

Remove the thermo and run a restrictor.
But that hose was going to go eventually.
I wonder if we can cap that pesky S hose altogether.

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[earlbrown]

I'm half drunk in a hotel room in Atlanta, so I'm going by memory here...


That S hose is a bypass hose. it's to keep the waterpump from cavitation while the thermostat is closed. If you block that with a cold thermostat in place, I have a feeling all hell will break loose while the engine's cold. Keep in mind if the coolant is sitting still, it'll start boiling above the exhaust ports and combustion chamber first... and steam is 1600 times bigger than water.....

I know they're expensive because they're so expensive but I have a feeling the S hose that fit's the hard heater pipe could be trimmed to work. I seems like I paid $5 for that hose when I built my engine a couple years ago.

 

[kidglok]

I'm half drunk in a hotel room in Atlanta, so I'm going by memory here...

A little early, no?

 

[earlbrown]

I got here on Thursday!

 

[71boss351]

I drilled two holes in the cone shaped outlet and installed two stainless screws in the holes. Then slipped the s hose over and reclamped the hose.

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[John Larkin]

Good thinking there with the screws. Innovative solution, will squirrel that one away for myself.

 

[Jan Larsson]

I drilled two holes in the cone shaped outlet and installed two stainless screws in the holes. Then slipped the s hose over and reclamped the hose.

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Aha didn't think about that; good idea ... just got it all apart and everything cleaned up ... will look and see if I can get a hole drilled (easy) and get two screws on there without taking it all apart (might be more difficult).

Not sure why they done that one cone shape and nothing to prevent the hose/clamp assy to slip off like on any other water nipple/pipe ..

Thanks for all the help and pointers.

 

[71boss351]

I couldn't figure the cone thing out either, its retarded. I personally almost had a stroke it kept coming off. I tried every clamp known to man, regular and a silicone hose kept having a problem. I thought I had ruined the motor. Finally, I drilled the two holes and put the stainless screws in there. I tried every type of clamp ect..... not much area to clamp too. I ended up with a regular clamp, no problems with that since.

 

[Jan Larsson]

I couldn't figure the cone thing out either, its retarded. I personally almost had a stroke it kept coming off. I tried every clamp known to man, regular and a silicone hose kept having a problem. I thought I had ruined the motor. Finally, I drilled the two holes and put the stainless screws in there. I tried every type of clamp ect..... not much area to clamp too. I ended up with a regular clamp, no problems with that since.

Did you drill and put the screws on there while all in the car or when you had the front cover on the bench? Drilling the hole just straight through will be easy and getting one of the two screws in wont be a problem however the second screw I can see being hard if on the opposite side (180 degrees apart); have to go our and see what might be the best option but if you got some pointers to help would be good !

 

[71boss351]

I removed as many of the things in the way that I could. Upper hose, basically anything that could go on and off easily. I was extremely frustrated at this point. I took a cordless drill and drilled two holes at around 10 o clock and 2 o clock. I inserted a small piece of shop towel to catch metal shavings. I then installed two small phillips head stainless steel self taping screws. I used a narrow regular stainless clamp with a new s hose and it worked great. I really tried every hose and clamp combo, small problem but it was extremely frustrating. My mind went nuts, thinking head gaskets, ect...... Good luck Steve PM me if you need any help.

 

[Jan Larsson]

I removed as many of the things in the way that I could. Upper hose, basically anything that could go on and off easily. I was extremely frustrated at this point. I took a cordless drill and drilled two holes at around 10 o clock and 2 o clock. I inserted a small piece of shop towel to catch metal shavings. I then installed two small phillips head stainless steel self taping screws. I used a narrow regular stainless clamp with a new s hose and it worked great. I really tried every hose and clamp combo, small problem but it was extremely frustrating. My mind went nuts, thinking head gaskets, ect...... Good luck Steve PM me if you need any help.

Drilled two holes @ 2 o'clock and 10 o'clock ... small no 2 self tap stainless screws in there and the heads creates a nice hump and feels like the tight clamp now sits nicely on the inside and wont slip off ... will double check before I put it all back together tomorrow.

Appreciate the help and hints on this one; hopefully problem solved and I wont have a similar experience again ... at least now I know which tools to bring if it ever happens again.

 

[earlbrown]

From the replies on the thread, blowing the S hose off sounds like a pandemic. Why have I never heard of this before?

Is it a chinese cover thing, or all of them?

 

[Jan Larsson]

Can only answer for myself and my cover is a high volume Mellinger (if I remember correct) cover; nice cover and no other issues with it.

Looking at the design the cone shape / tapered hose connector on there with no ridge to hold the hose in place I can see it happening as I was surprised when I looked closer at it. Compare to the water pump hose connector for the heater circuit ... that's the design I would have expected to see preventing the hose to slip off and also provides a secure way once the clamp been tightened down.

 

[earlbrown]

Melling. It's pretty much the same chinese unit as the Elgin, Pioneer, etc... I'm curious if the OD is smaller than it should be and a small worm type clamp pinches up a spot compromising the clamp load.

I never mess with those so I don't have one handy to see the difference. The GM covers don't have a lip cast into them but I've never heard of them having a hard time retaining the hose before.

 

[Jan Larsson]

Here's a photo of my front cover when I built the engine back in 2008 or so.

Measured it earlier today (all metric) and you can see the taper (from 19.3mm down to 17.6mm) which is cheaper to manufacture however not ideal for the clamp.

My problem I found out when I took it all apart at home were the constant tension clamps I use and for some reason I had put a size too large on the s-hose; so now when put together I used a smaller size specified for the hose / nipple dimension. The two screws I put at the end per above post is just "peace of mind" really.

S-hose is 19mm (give or take) inside diameter so fits good on there.