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Discussion Starter · #1 ·
I decided to change the coolant on my 4720 - I was reading a thread on TBN about some mysterious leak that can occur on these engines and one possible cause is old coolant corroding the timing cover seal (I think). In addition, I have not changed the coolant since buying it and, for all I know, it still has original coolant (5 years old). I bought the JD Coolgard coolant as recommended in the manual and following the procedure for draining, flushing, etc. I used Prestone flush as that was what I could find locally.

Now the radiator has sprung a small leak from the front (low down near the center). It's big enough to drain the recovery tank in 15 minutes. Now, a few things are on my mind - first, should I change the radiator or try one of those Stop Leak products? Is it possible to repair a small leak like this? A new radiator isn't too bad, $285 according to JDParts.com so it's probably not worth the hassle of a bad repair.

Second, I'm trying to figure out the cause of the leak. Now, I've used it pretty hard over the past few weeks (clearing some land) and it's possible that a branch may have poked through from underneath. It's actually quite likely. However, it was not visibly leaking and at least 2 gallons of coolant drained out (and the recovery tank was at the right level). Another idea is that maybe Prestone flush was not a good match? Another theory is that there was some "stop leak" already in the system and I flushed it out thus opening the leak. The coolant that came out was standard green coolant implying that the coolant had been changed at some stage.
 

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I decided to change the coolant on my 4720 - I was reading a thread on TBN about some mysterious leak that can occur on these engines and one possible cause is old coolant corroding the timing cover seal (I think). In addition, I have not changed the coolant since buying it and, for all I know, it still has original coolant (5 years old). I bought the JD Coolgard coolant as recommended in the manual and following the procedure for draining, flushing, etc. I used Prestone flush as that was what I could find locally.

Now the radiator has sprung a small leak from the front (low down near the center). It's big enough to drain the recovery tank in 15 minutes. Now, a few things are on my mind - first, should I change the radiator or try one of those Stop Leak products? Is it possible to repair a small leak like this? A new radiator isn't too bad, $285 according to JDParts.com so it's probably not worth the hassle of a bad repair.

Second, I'm trying to figure out the cause of the leak. Now, I've used it pretty hard over the past few weeks (clearing some land) and it's possible that a branch may have poked through from underneath. It's actually quite likely. However, it was not visibly leaking and at least 2 gallons of coolant drained out (and the recovery tank was at the right level). Another idea is that maybe Prestone flush was not a good match? Another theory is that there was some "stop leak" already in the system and I flushed it out thus opening the leak. The coolant that came out was standard green coolant implying that the coolant had been changed at some stage.
I don't think that I would use a stop leak product, I've always been afraid of plugging the heater core. I would probably take it out and bring it to a radiator shop for an opinion. He will be able to advise you on the possible cause, and any compatibility problems with the Preston flush. He may be able to fix it for $100.00. Like you said, your worst case scenario isn't too bad at $285.00.
I would check closely for battery acid damage.
 

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I don't think that I would use a stop leak product, I've always been afraid of plugging the heater core. I would probably take it out and bring it to a radiator shop for an opinion. He will be able to advise you on the possible cause, and any compatibility problems with the Preston flush. He may be able to fix it for $100.00. Like you said, your worst case scenario isn't too bad at $285.00.
I would check closely for battery acid damage.
I agree with Arlen. A stop leak product is great for junk yard beater cars and that's it my mind. You potentially block more than just the leak when you use them. I hate to have to spend more time and money to fix something right the second time because a shortcut screwed me the first time.:thumbsdown:
 

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I agree with Arlen and DS. Stop leak products are usually not a good choice for things you want to last. You'll usually wind up having to do larger repairs down the road to fix what the stop leak plugged up.
 

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Discussion Starter · #5 ·
Thanks for the feedback. I ordered a replacement from the dealer. According to the parts guy, there's no one in town that fixes these things anymore. I will install the new radiator and look into fixing the old one as a spare. It's just a pin hole leak in the front, shame to junk the radiator. The price wasn't too bad though -and it looks fairly easy to get out.
 
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