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Anybody know the size of the Orings that fit on the solid tubes going into heater core. I picked up the wrong size ID 1/2 OD 5/8. Can call and ask wife to pick up, would be nice to have truck back on the road for the morning.
9/16ths ID 3/32ths width 3/4th seemed a bit to easy to reassemble.
Toyota gave me their "aftermarket" 15mm ID 2.5mm width Orings that felt much tighter to reassemble.
FYI: Orielly's parts
Murray Part Number: 399321 would not accept the factory copper extension tubes and seal the same way as factory perhaps RTV would have sealed it up, did not try.
Murray Part Number: 394179 would not fit in the holder too large.
Spend several days soaking in CRL got alot of crud out and increased flow through.
I just finished the heater core in my 86 longbed, and the 399321 fit just like the original. After pulling the old core, it became apparent that whoever had replaced the core the last time had used standard duty o-rings and they has melted over time and started to leak. I tried to get the o-rings from Toyota, but they were a week out and $5.99 each. I went down to our local Fluid Connectors store and picked up a couple of Viton (high heat) orings in the 9/16 ID x 3/32 thickness for $.33 each. They were a bit on the tight side, so if I had it to do over, I would suggest the 9/16 ID x 1/16 thickness in the Viton material.
One more word of advice, it really sucks to find out that one or more of your bulbs didn't make it during the installation. I replaced all of the bulbs while I was in there, keeping me from having to find out the hard way that one of them was overdue to quit.
I know this is a really old post but, I believe this info would be beneficial to anyone getting ready to replace their heater core.
I replaced my heater core about 10-11 years ago and of course the new core didn't include the necessary O rings (why!!!) and I couldn't find the correct O rings anywhere (dealer didn't have them) and was forced to reuse the old ones as, I needed to drive my truck to work on Monday (it was Saturday).......fast forward to now.
I again need a new core (weak heat output, smell of coolant and greasy mist on inside of windshield)......
dealer doesn't even have a part number for them (thinks but, not sure they might be included with clip kit @ $8 each X2), long story short Mc Master Carr has the proper size(?) 15mm ID X 2.5mm thick O rings, pkg of 100 for about $6!
Hans
Thought I post a follow up after 8 yrs the 15mmx2.5mm o-rings were still going strong. Heater core needed a bit of TLC so had it cleaned. I thought I'd throw a set of 9/16X3/32 in, well less than 2 months I'm back replacing them again due to leak. I did use nitrile vrs the viton mentioned above perhaps that made a difference??? Will get the metric one this time.
As mentioned above I had heater core rod'd out as it it was badly clogged. I replaced the o-ring with a 9/16X3/32 o-ring from a multipack from Habor Freight. Afterwards I smelled coolant from time to time but had a coolant leak here and there so thought it was just a loose connection. Last Saturday o-ring gave way. Replaced with a new o-ring with a different brand and decided to pressure test core. Got the idea from a cruiser guy on IH8MUD. Worked like a charm and cost about $5. I pumped pressure up a bit too high really should be pressure tested at 15psi. New o-rings help fine, watched it for 10min with no bubbles. After releasing pressure, most of it anyways. I felt pretty confident about repair. Till.... while loosing hose clamps one of the extension tube popped right off. Best guess is the channeled C clips being old were past their prime. So had extension tubes soldered to the core. Sorry no pics after solder work, I suck at soldering and was short on time so paid to have soldering done.
Last edited by muddpigg; Feb 16, 2018 at 06:53 PM.
As mentioned above I had heater core rod'd out as it it was badly clogged. I replaced the o-ring with a 9/16X3/32 o-ring from a multipack from Habor Freight. Afterwards I smelled coolant from time to time but had a coolant leak here and there so thought it was just a loose connection. Last Saturday o-ring gave way. Replaced with a new o-ring with a different brand and decided to pressure test core. Got the idea from a cruiser guy on IH8MUD. Worked like a charm and cost about $5. I pumped pressure up a bit too high really should be pressure tested at 15psi. New o-rings help fine, watched it for 10min with no bubbles. After releasing pressure, most of it anyways. I felt pretty confident about repair. Till.... while loosing hose clamps one of the extension tube popped right off. Best guess is the channeled C clips being old were past their prime. So had extension tubes soldered to the core. Sorry no pics after solder work, I suck at soldering and was short on time so paid to have soldering done.
Would you mind sharing a picture of the solder? I'm going through the same thing, and I'd like to see how it was done. Seems insane that this is the best solution.
Dec 7, 2010 | 06:01 PM
