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Speedymaru

78 620 lower heater core hose?

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Hi, my 1978 620 just started leaking coolant pretty bad. I’ve located the leak, and it’s on the lower heater hose. I could not find a link on where to purchase one. Can I use generic heater hose? Or is there a link? Thank you very much 

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Disregard the post. I found the part after doing more research. Sorry for the waste of time. Is there anything to look out for when replacing the lower hose?

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Use generic hose, I did. Change them both while the coolant is drained. If replacing them anyway remove the hose clamp and slit them lengthwise and peel them of the fittings. This will prevent straining the solder joints

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13 hours ago, Speedymaru said:

 Is there anything to look out for when replacing the lower hose?

As with any heater core, do not use pliers to remove the old hose. Heater cores are usually made of brass (or aluminum now days) and the hose nipples are very thin and very soft.

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Well I messed up 😐 I got the front end of the hose off with no problem, but the back part was a major struggle. Rounded off the bolt on the hose clamp, and ended up breaking off the heater core nipple. Not sure what to do now. Afraid I might have to buy a replacement 

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I decided to just bypass the heater core for now. It will be temporary. The truck is my daily driver so I needed to get it going at least for now

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Best to plug both hose ends rather than joining them.

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Will it hurt anything if they’re connected for a little while? If it does then I’ll plug them 

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Hell no, not a problem not at this time of the year. That hot water from the head is either shut off or running through the heater. If you by-pass it, it goes right back into the engine un-cooled. On a very hot day this would be a bad idea.

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Well I guess you don't have to worry about using a pliers to get the hoses off the heater core now...

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Alright, thank you. Gonna try to drive it today. And yeah, I feel like an idiot for breaking that off...

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Hey, so I’ve been driving it with the bypassed heater core, and it’s been much better. Is it normal for the temp to be much lower than before? It now stays in the far cold area for about 15-20 minutes of driving, then it will go up to about 1/4 of the way to hot. Is this normal?

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By the way, I used about 4 feet of hose because I plan to fix the heater core and do it correctly eventually 

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Replace your thermostat with a new 180-185F.  In 10 min of driving it should be into the middle of the range. Engines are designed to give best performance and mileage running at operating temp. You should get there as soon as possible. My 710 sedan was slow to warm up and stayed very low on the gauge. I took it out and it had a rubber seal that had puckered....

 

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The thermostat can also just stick or it may be the type that fail in the open position. I never test them it's a waste of time. You have to remove and clean the surfaces and put a new gasket on anyway so just put a new one on.... and spend $10 and get a good one not a WallMart $2.99 POS either. The thermostat is crucial and has to work properly ALL the time.

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