rcb280z Posted April 4, 2019 Share #1 Posted April 4, 2019 (edited) On my 77 280 stock engine.......... Besides replacing it completely, which I have no time for right now, can anyone recommend a head gasket stop leak? One that has worked / known to work. I know, I'm probably asking for a miracle. The first pic show's a leak at the back corner right side that is new. Not at the freeze plug. The second pic is a leak, seepage between Nissan and Japan, between #2 and #3 spark plugs, that has been there for years. Have just kept and eye on it. But now with the new leak I'm concerned. I will eventually pull the head and replace the HG but not right now. The new leak seems to stop after the engine has come to full operating temp. It's not leaking into the cylinders. Plugs don't show that as a possibility. No miss on start up. No puffs of white smoke / steam. Engine doesn't overheat. Appreciate your input. Bob Edited April 4, 2019 by rcb280z added content Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/ Share on other sites More sharing options...
Zed Head Posted April 4, 2019 Share #2 Posted April 4, 2019 Is that the top of the block, near the heater hose in the first picture? I had that same leak n my 76 engine. Barr's Stop Leak worked for a while. It eventually extruded through the gap, leaving a small pile of powder back there. You could also buy an OEM stop leak. Ford has one. I've seen the part number but don't have it handy. Looks like GM has one too. You could probably go to a Ford Dealer and ask for stop leak pellets and they'd know. Here's an example, but I've seen it in my Ford service manual also. https://forums.tccoa.com/7-engine-4-6l-5-4l/121432-ford-suggests-stop-leak-their-new-modulars.html And, of course, you'll take heat from the "do it right" crowd. Even though Ford adds it at the factory in new engines, apparently. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572612 Share on other sites More sharing options...
rcb280z Posted April 4, 2019 Author Share #3 Posted April 4, 2019 28 minutes ago, Zed Head said: near the heater hose in the first picture? Close, it's right at the corner of the head / block. IIRC there is a large coolant passage there, next to the head bolt. 32 minutes ago, Zed Head said: 30 minutes ago, Zed Head said: you'll take heat from the "do it right" crowd Rightfully so. I totally plan on replacing it......soon. 33 minutes ago, Zed Head said: Ford adds it at the factory in new engines Interesting, I did not know this. I'll put that on the list of possibilities. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572617 Share on other sites More sharing options...
Mark Maras Posted April 4, 2019 Share #4 Posted April 4, 2019 So how does one get the stop leak out of the radiator and heater core at some future date? Doesn't the stop leak restrict the coolant flow? Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572624 Share on other sites More sharing options...
rcb280z Posted April 4, 2019 Author Share #5 Posted April 4, 2019 I've wondered the same. Maybe it doesn't restrict flow? Only builds up, hardens, where there is an air source? Just guessing right now. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572625 Share on other sites More sharing options...
Zed Head Posted April 4, 2019 Share #6 Posted April 4, 2019 Pretty sure it just jams up small holes. Flows right through the big ones. Doesn't harden that's why it kept squeezing out the relatively big leak at the back of the head. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572632 Share on other sites More sharing options...
rcb280z Posted April 4, 2019 Author Share #7 Posted April 4, 2019 Harden was probably not the right word. Maybe "thicken" describes it better. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572633 Share on other sites More sharing options...
siteunseen Posted April 4, 2019 Share #8 Posted April 4, 2019 1 1 Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572635 Share on other sites More sharing options...
rcb280z Posted April 5, 2019 Author Share #9 Posted April 5, 2019 (edited) That's funny Cliff. I was going to post the stuff they have in a spray, as a joke. Edited April 5, 2019 by rcb280z Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572641 Share on other sites More sharing options...
Mark Maras Posted April 5, 2019 Share #10 Posted April 5, 2019 Is it possible we'll see a Z in a future Flex Seal commercial? Repairing the leak with Flex Seal might be worth a try as a temp. fix. If it works, imagine what could be next, rockers, doglegs, wheel arches, floors, and frame rails all bonded with Flex Seal products. Fame and fortune in commercials could be just a stupid idea away. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572644 Share on other sites More sharing options...
rcb280z Posted April 5, 2019 Author Share #11 Posted April 5, 2019 (edited) 1 hour ago, Mark Maras said: Is it possible we'll see a Z in a future Flex Seal commercial? Repairing the leak with Flex Seal might be worth a try as a temp. fix. If it works, imagine what could be next, rockers, doglegs, wheel arches, floors, and frame rails all bonded with Flex Seal products. Fame and fortune in commercials could be just a stupid idea away. So are you trying to tell me that's how much faith you have in any head gasket stop leak? Edited April 5, 2019 by rcb280z Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572652 Share on other sites More sharing options...
Mark Maras Posted April 5, 2019 Share #12 Posted April 5, 2019 Well, In an emergency, but little beyond that. The size of the pellets in some stop leaks make me wonder how much ends up plugging cores rather than stopping a leak in a specific place. It's probably my own ignorance of how the product works. Years ago I used a silver powdery stop leak that worked very well. I seem to remember the name being Silver Solder Stop Leak or something like that. Link to comment https://www.classiczcars.com/topic/61949-hg-stop-leak-recommendations/#findComment-572655 Share on other sites More sharing options...
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