Good morning bus folk,
Somewhere, around our re-cored radiator on the passenger side (our 1983 MC9 has two radiators), I have coolant leak(s). I've spent a lot of time up there looking and am having trouble finding the source. After having them replaced, I had a small issue w/ some of the hose clamps coming loose, but I've fixed those issues. I've torqued those smaller clamps to 50 inch pounds and that stopped all leaking around those hoses.
At the top of the radiator there is the hose that runs from the surge tank to the radiator, with a small, about 18 inches, hose. It seems to be damp around the connector on the hose. So I'm looking for a replacement for that just in case. However, it doesn't seem likely that is the sole cause of the issue. Mechanic said 10 foot lbs torque for that connector, I think I was able to check that connection but it didn't seem loose. I can give it another try if that is recommended.
The other area I have a question on is all those bolts around the top lip of the radiator, could those need tightening? After the radiator was initially put back in and tested, nobody noticed any problems. Only after it was driven a while in the mountains and deserts that this started.
As usual, greatly appreciate your advice!
Kind Regards, Phil
Looks like the gasket on the top tank is leaking. Did you replace that when you recored the radiator?
Thanks Craig,
The entire radiator was replaced. (Both radiators were replaced). The originals were not recored.
- Phil
I bet the gasket is leaking too. Mine did on my 102C3. I tightened down all of the bolts along the top of the radiator and fixed that problem.
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When I recored my radiator it took several slight retightenings of the tanks' bolts until the gasket no longer compressed. I then pressurized the radiator and tanks to exactly 10 PSI and made sure there was absolutely no pressure loss after 24 hours.
Also, if you are using any silicone hoses, they should use constant-tension hose clamps instead of the usual cheapo clamps. C-T clamps prevent silicone hose from weeping, especially in cold weather.
John
PRESSURE TEST
4-6 psi won't hurt a radiator but it makes leaks obvious.
need a regulator on access.
i built my own.just stay under the cap pressure.
ps. you can over torque a radiator gasket.
not all grades of radiator tank gaskets are equal
Thank you all!, I referenced a guide which said 57 ft. lbs. for 1/2" grade 5 bolts. Head markings look like grade 5. However, would the torque be different for those radiator bolts due to the seals between the metal? What guidance would you give for tightening those bolts? I tried a few and they were definitely loose. Some were not.
What i've learned to this point from what you all have said is that those bolts are basically holding the tank together - and if they are loose or the seals bad, then I will experience coolant leakage.
My maintenance manuals don't show exploded views of the radiators so I appreciate all the information. Much to learn.
Best Regards, Phil
Where are these 1\2 inch bolts? You're not referring to the radiator tank bolts are you? They look to be about 5/16 or 3/8 inch diameter.
http://www.almabolt.com/pages/catalog/bolts/tighteningtorque.htm (http://www.almabolt.com/pages/catalog/bolts/tighteningtorque.htm)
57 ft lbs is incorrect for any 1/2" bolt, either shaft diameter or head size. 1/2" head size is 5/16" thread, torque should be around 15 ft lbs, or "nice and tight" with a six inch wrench.
Thank you! The heads require a 1/2" socket.
Perfect information w/ regard to torque and "nice & tight" w/ 6 inch wrench. ;D
I'll head out & do some snug tightening.
Is there a pressure test kit which would work well for these radiators? I did a few searches and uncovered quite a large volume of product. Just not sure which would fit.
Kind Regards, Phil
When I snugged down the nuts of my tanks' bolts, I used a screwdriver-handled 1/2" deep socket. (Mine are 5/16" bolts, and I used new stainless-steel fasteners with lightly-oiled threads and lock washers.) Using a wrench like that prevents overtightening! As soon as the gasket began to squeeze out, I stopped. I used Johnson 235-24 cork gasket tape (the thick green one), and its instructions stress to not overtighten the bolts.
One thing that makes it easy to pressure-test cooling systems to help find leaks is to put a Schrader valve on the surge tank's upper vent hose. I hope I'll never need to use it.
John
I'd recommend a sequence of tightening every 3rd bolt working around the tank 3 times to get all of them snug. Then do it again for the final torque. Similar to torquing a wheel. Slow and even.
Funny, all this talk about torque and method. I literally just tightened all my bolts down using my own arm strength and a normal 6 or 8 inch socket driver and I have zero leaks now (with 13,000 miles on the newly tightened radiators). So agonize over it however you want to, but likely tightening those bolts will solve or slow your issue.
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Scott's way works best for me too.
Infact slowwwwly tighten until you think the gasket will compress....
Once it protrudes beyond the core and tank...you have (possibly) ruined the gasket.
You don't want it to extrude.
From that point...the gasket cracks.
the seal in the hole circumference might be 1/4 inch of material.
when i built radiators..i used a 1/4" air ratchet.
tightened to contact
and finished by hand wrench and eye.
ps when i said torque...i didn't mean to imply torque wrench
Ha Ha - Scott - I'm pretty sure Craig knows my lack of mechanical genius. Remedial and basics, how-to, are always appreciated by me. My daytime world is completely different than my bus world. With much to learn.
I'm being sent out of town soon for company work in a couple of days, so trying to gauge level of effort & what I can get done before leaving. Juggling day job & runs out to the bus to check/tighten. Then as soon as I return need to take the bus down to another location. Hoping not to be trailing coolant. :-\
Thank you!, Phil
Oh for Pete's sake. More testing - under a little pressure and with more lights (it's dark back there above the radiator) - showing coolant is actually dripping down from above down onto the radiator lip w/all the bolts. So maybe it is originating from the coolant hose / connection that goes to the surge tank. That connector on the radiator side of that hose looks very wet.
Best Regards and happy Sunday, Phil
Quote from: plyonsMC9 on October 01, 2017, 07:55:44 AM
Oh for Pete's sake. More testing - under a little pressure and with more lights (it's dark back there above the radiator) - showing coolant is actually dripping down from above down onto the radiator lip w/all the bolts. So maybe it is originating from the coolant hose / connection that goes to the surge tank. That connector on the radiator side of that hose looks very wet.
Best Regards and happy Sunday, Phil
Crank all those hose clamps down. They are notorious for leaking during cold weather. You should have constant tension clamps on all hoses, but even those need to be tightened from time to time.
Thanks Craig, No hose clamps on that particular connection. I think i have to tighten these almost by feel. And some acrobatics. Is the bottom nut part of the radiator, and I'm just tightening the upper connection nut? Or both -not quite sure what I'm doing w/ it. Remedial questions I'm sure, but I just spent a lot of $ on this radiator and don't want to make a mistake - it's pretty difficult to reach.
Kind Regards, Phil
Quote from: plyonsMC9 on October 01, 2017, 06:23:54 PM
Thanks Craig, No hose clamps on that particular connection. I think i have to tighten these almost by feel. And some acrobatics. Is the bottom nut part of the radiator, and I'm just tightening the upper connection nut? Or both -not quite sure what I'm doing w/ it. Remedial questions I'm sure, but I just spent a lot of $ on this radiator and don't want to make a mistake - it's pretty difficult to reach.
Kind Regards, Phil
that hose appears to have no swivel...and so, the other end needs to be taken off and the whole hose tightened...if i understand what you say is leaking.
further, that is a "less than acceptable" way to configure a hose....even if it isn't leaking.
hopefully that is not OEM, imo.
You need to blow it dry first. If you then spray it with talcum powder, you can see where it is leaking; at the 45° elbow or at the inverted flare connection above it.If it is the elbow, since it has to be pointed a certain way ( most likely ) or the connection to it from the fitting on end of hose, you will need to remove elbow and rewrap it with Teflon tape or pipe sealant. Because the elbow has to be indexed properly, if it is the connection leaking, you should consider getting a new elbow. Many times you cannot tighten it enough to go an additional turn, so it has to be looser than desired. If you use one of these, you can easily access the connection with a ratchet, extension, and maybe a universal joint. I've used these a lot over the years for hard to access connections. They also make crows foot type to turn elbow.
https://www.harborfreight.com/7-piece-sae-crowfoot-flarenut-wrench-set-93137.html (https://www.harborfreight.com/7-piece-sae-crowfoot-flarenut-wrench-set-93137.html)
I just took a look at mine. It appears you can get in there through the radiator doors. It looks like there is a swivel on the hose (middle nut in your photo). I'm unclear, though, where you are seeing fluid. Is it on the fitting, or on the hose. These types of hoses are known to crack internally when under stress such as a bend in the hose. Drain the coolant level down below the surge tank level and pressurize the system with shop air, if you can, and use a soap mixture to spray the hose to see if you have leaks.
Many times you cannot tighten it enough to go an additional turn, so it has to be looser than desired.
which is one of the benefits of more teflon tape...
I ended up replacing my hoses up there (the ones with the brass ends that went from the overflow to the tops of the rads) with custom made new ones from Pirtek hose. No leaky.
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Thanks very much to all for the expert direction. Deeply appreciated. I ended up having to leave town for a work trip to D.C. today, so we had a mechanic come out to finish up so we could travel in the bus as soon as I returned.
What the mechanic found was that 'upon installation, someone had cross-threaded the hose into the tank'. That was the hose in the last pictures. 4 hours of labor later (well-spent IMHO), he had fixed the threads, replaced parts, etc., according to my wife who is back at home. Expensive but glad it is fixed.
As you may know, I just had recored radiators put in a couple of weeks ago, so I'm fairly certain that the shop doing that work caused the error as it was leaking during the next use of the bus. Going to ask that shop to help me out with a few $$ for a large job they are working on now for us, as this cost was $500 to stop the leaks. I had let them know w/in a couple days of the replacement that there was an issue w/ leaking coolant. Stuff happens, and the rest of their work was well done.
Kind Regards all, Phil
Quote from: plyons on October 02, 2017, 08:35:42 PM... we had a mechanic come out to finish up so we could travel in the bus ...
Sometimes that's the smart thing.
Quote from: plyons on October 02, 2017, 08:35:42 PMWhat the mechanic found was that 'upon installation, someone had cross-threaded the hose into the tank'. ... 4 hours of labor later (well-spent IMHO), he had fixed the threads, replaced parts, etc., ... Expensive but glad it is fixed.
Quality work at the right time is worth it. It's good you got it fixed and know it's fixed - right.
Quote from: plyons on October 02, 2017, 08:35:42 PM... this cost was $500 to stop the leaks. ...
You got a good, experienced person to come to do excellent work that you needed and spent four hours doing it. Yeah, it's not cheap but that's sure a fair price.
Thanks for that response Bruce,
I tend to second guess myself. So good to hear the encouragement. I'm very thankful for the mechanic's knowledge and ability to solve the issue. And I'm positive that is a fair charge - that's a tough place to operate. :P
And even more positive is that the company that did the radiator install is going to work with the mechanic who fixed the issue, with the goal being to offer some credit against upcoming mechanical work.
No bad feelings at all on my part as I know from too much experience that not every install or fix goes perfectly.
Case closed on this one!
Kind Regards, Phil