Hello all! My 92' ST started and ran fine today but left a puddle of coolant on the shop floor after idling as it warmed up for its' season end oil change. The trail of coolant came down just in front of the left foot peg . After removing plastics the fluid trail was traced up behind the center of the engine and out of sight, my next step will be to pull the fuel tank for a better look. Does anyone know where I'm headed with this? The bike just turned 20k miles and is immaculate( other than a coolant leak!) any help much appreciated!
Coolant leak
- Thread starter Dbeelinvt
- Start date
Given where the leak escaped, you would be looking at the one of the two hoses that connect the heads to the thermostat, these also leaked on mine. After the tupperware is off, you need to pop the airbox and carbs out to get in here. My advice would be to replace all the coolant hoses, plus the elbows that bolt to the heads, and the o-rings under the elbows. If you take the carbs off, you might also want to invest in new carb rubbers as the old ones will be stiff and make remounting the carbs even less fun than you'd imagine. And seeing as the carbs are off, why not put a new fuel filter in as well. All available from a Honda parts dealer, I used Partzilla earlier this year.
Don't forget to replace the two elbows. Didn't see em mentioned in the above link.
Here's a parts list for the job. For the bulk hose if you want I will send you a foot of it for free, PM me your home address. The other item "tube" is the hose in the front of the carbs, you may not need it, but I mangled mine a bit removing the carbs so I added it on. I recommend removing everything before you order your parts, just in case you have any unexpected problems or issues, then you can get everything in one order
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.Great info, thank you so much! I will continue digging in this weekend after taking some pictures and getting some better heat in the shop. You're right about waiting to order parts til the disassembly dust settles as there is quite often a surprise. Any urge to replace the thermostat while in the neighborhood?
No reason not to, and there are auto t-stats that replace the OEM one. From the ST archive of wisdom:
Thermostat:
1973-80 Honda Civic 1.5L 180 deg
Stant's old number: 35868
Stant's new number: 13868
RobertShaw "Generation2" part # GT753-180
However, t-stat replacement as I recall is a pretty simple process (as in easily accessible without removing more than a few fairing pieces), so if you decide to do it later its no big deal.
If you do choose to replace the thermostat, you will probably also need the big o-ring on the t-stat housing. Certainly an easy job when the hoses are off, less fun when the hoses are attached.
not true, you can separate the two halves of the t-stat housing with the hoses attached, and put a new t-stat (or O-ring) in the housing. As I recall you just have to remove the fairing plastic bits around it, and the little plastic shroud in front of it, then you have access to the bolts that hold the two halves together. I tried reusing the old O-ring because I couldn't get my hands on a new one right away, and it leaked. Then I went back a day or two later after I picked up a new O-ring and finished the job.
Any nerve calming suggestions when it comes to removing thermostat housing bolts? As a kid I had one break off in a 75' Civic that tied up my Dads garage for a week! I'm supposed to be wiser now!
my bolts were clean, no issues. Haven't heard much on this forum regarding problems in that area, so I wouldn't worry too much about it. And even if a bolt snaps off, the rear half of the t-stat housing is a $55 replacement part if you can't get the broken bolt out cleanly.
I was more concerned about the bolts that hold the coolant elbows into the engine, those get pretty gnarly looking over time. When you pull those elbows out the old O-rings will probably look like black goo smeared into the cutout, which makes it easier to just replace the entire elbow with a new O-ring. Also, don't try to re-use the old elbow, some people have cracked them on re-installation.
.........Agree and also would replace the four carb intake boots with new OEM from Honda. Pay attention to original carb boot orientation for correct clamp access, as clamps are held stationary on carb boot with a locator pin on each clamp. Prior to installing carb bank, silicone spray inside of already mounted carb boots.......helps carb bank drop nicely into boots in correct location.
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You folks are great, thank you! You've probably just reduced my cussing down to two for the procedure. I will continue to prep the patient for surgery.