I think I ruptured the coolant bypass.....

[Dijadoit]

I was driving to work today and was waiting at the stop light then a plum of steam came out from under the hood. So I pulled over and it was coming from under the exhaust manifold. I'm assuming that the return line coming from the heater core re-circulating back towards the water pump, heh....

So my assumption that is the coolant bypass, is there a better way to re-route that around and away from the exhaust manifold?

I was thinking about pulling it off and cutting the pipe and buy a heavy duty rubber hose that can handle the pressure and heat from the local auto parts store including very good clamps. Re-route towards the radiator instead of passing the underside of the exhaust manifold.

Any opinions would be appreciated for a better route or its not a good idea...

I guess do to age and metal fatigue plus recently installed a new water pump, the pressure built up and the pipe decided to bust open on a bad day.

[bam]

Strange, I've actually heard of this happening before. I think the pipe is just so thin walled, combined with corrosion and heat makes it go. You'd propably be fine with some high temp tranny cooler/oil cooler type hose. I wouldn't really trust regular heater hose. If it was me I'd go to the dealer or a junkyard and look for a clean metal pipe.

[therieldeal]

did you replace the o-ring on the end of it when you did the water pump? if not, its probably just that.

if you look around the junkyard, some BP's actually had aluminum bypass pipes... my 91 EGT did but my 95 did not. neither did my 93 tracer, or the GTR motor for that matter. if you can find one of those you should be golden...

[MATT91GT]

what were they otherwise? steel?

[ftjandra]

what were they otherwise? steel?

Yes, the one on my '94 was steel. I know because I welded a fitting onto it.

--Ferdi

[therieldeal]

yeah, steel... and they rust pretty easily. i sandblasted and powdercoated the GTR one to try and prevent that.

[Dijadoit]

Well to double check, I warmed up my car turned the on the fan then switch to heat to let the coolant into the heater core; boy that pipe was spaying a bit, definitely not the o-ring.

[therieldeal]

coolant flows through the heater core all the time..

[Dijadoit]

Is there a way I can stop the flow to the heater core? The controls on the car are cable operated versus vacuum, there gotta be a valve that I can disconnect a cable to keep it shut. Until I can repair it later....

[ftjandra]

Nope, there is no valve. Coolant always circulates through the heater core. All the cable does is move a flapper to block air from blowing through it. And, it's not just the heater core that attaches to that pipe. I think there is also a small hose from either the throttle body or isc wax valve.

--Ferdi

[jumpncrash]

its the ISC actually, but that metal pipe is a POS, every time I see a good onoe now I grab it

[Dijadoit]

I might have figured out a way, some of the old Honda's during the late 80's to early 90's had a valve located in the engine compartment that was cable operated which controlled a coolant flow into the heater core. If the hose diameter matches it might just work, I just cut the left hose, which I'm assuming is the input and install the valve there shut it off temporarily till I find the replacement bypass that is in good condition.

[Kitty]

Instead of going to all that trouble wrap it with plumbers tape and drive to a junkyard and pic one up.

[Dijadoit]

Yes, I found a honda shut off valve in my garage. And the piping is matching diameter, won't be able go to the junkyard until later. I need to get bathroom project done first. Its summer time, I don't need heat till fall anyway.

[Dijadoit]

Well installed the the coolant cut off valve, then I found out the little hose that connects from the bypass to the thermostat housing right by the sensor has a leak; I decided to cut that hose in half and plug the ends with a bolt.

Now my temp gauge goes way pass the middle when idling at the light and back to normal on movement; plus my fan stays on a little longer than normal.

So assuming that little hose flows a little bit of coolant by the thermo sensor to give an accurate reading for the temp gauge and tell the fan to kick on? Am I right?