Mystery: Coolant leak stopped?

[Eric1971]

Looking for some ideas on a mystery!

I've had this 1995 Explorer Eddie Bauer for about a year now (1 previous owner, 140k miles) and done a lot of little fix-it jobs on it, most of them helped greatly by info from this forum! On the first shop visit, the mechanic told me the seal on the front of the block was leaking coolant and would be $1200 to replace. (I understand the details of how that works) He advised it should be fine for my 3 mile commute as long as keep an eye on the coolant level, which I check weekly. At some point, I also noticed a very small coolant leak at the top transmission cooler fitting of the radiator as well. Up until recently, it's been going through a gallon jug of coolant about every 4-6 weeks.

A few weeks ago I noticed the serpentine belt was looking very old and cracked on both sides, so ordered a new one. It only took 5 minutes to replace. Ever since the new belt, the coolant leak has seemingly disappeared or at least drastically reduced. I haven't had to add any coolant at all the past two weekly checks.

I don't want to look a gift horse in the mouth, but I cannot think of any reason that the new belt would have this effect. Could something have been causing too high pressure in the cooling system due to the old worn belt? The temperature always ran normal, maybe seems a little lower now even though the weather has gotten warm. The old belt never made noise, it was just obvious it was time to replace it.

Any theories are appreciated, thanks!

 

[Turdle]

Timing cover leaks are usually at their worst at around 35-40 degrees, and will often leak less when warmer weather sets in. Also, due to the warmer weather you are probably using the heater less which makes it seem like the coolant is at a higher level because the heater core is empty of coolant.

so, to check this, With coolant cold, Start the engine, turn heater on hot floor, then check the level in the radiator itself .

In fact, the low level coolant ( heater core empty) could be why no coolant is being pushed out of the timing cover.

Just a hunch. Your actual experience may vary.

 

[masospaghetti]

Better yet, go to Autozone and get their free loaner kit to pressure test your coolant system. It's 100x easier to find leaks when the engine isn't running (and you're worried about getting caught up in the fan). this also lets you pressure test with a cold system.

I thought for sure i had a timing cover leak and had already bought the parts for the job. I used the tester kit and found that my lower radiator hose wasn't clamped down enough! I've also found multiple heater hose connections leaking that needed new hose clamps.

$1200 for a timing cover leak seems a bit steep IMO. If you are reasonably handy it's certainly a doable job. I have had to do it multiple times (and it's far easier to do on the 4.0 than the 5.0).

 

[Eric1971]

Thanks, everyone. I got the pressure tester from AutoZone. All I could find was the minor seeping leak on the radiator at the top transmission cooler line fitting, and definitely a leak at the timing cover. The radiator leak is coming from behind the washer against the radiator. I tried snugging up the big nut but it looks like that's permanently attached to the radiator (based on replacement pics I'm seeing) so I didn't put too much pressure on it. I think that is going to require a new radiator or is it possible to seal around that with something like JB Weld?

I'm sure there's lots of good info here on the timing cover seal so I'll go look for that. I'm definitely handy but have my limits. Example, I've replaced myself the brake pads/rotors and flushed the lines, replaced all of the shocks, changed oil, new tire winch, etc but I had a shop replace the fuel pump (I don't drop fuel tanks!) and the starter (seemed very hard to reach).

Thanks again.

 

[Eric1971]

K-Seal worth a try?

 

[BruceExploder]

K-Seal worth a try?

K seal is worth a try

 

[donalds]

K seal

 

[Eric1971]

Thanks. Got the K-Seal and put it in yesterday (following all instructions). After putting in new plugs and wires yesterday, I cleaned the engine a little last night so I could more clearly see if the radiator fitting leak is stopped. It appears to be so far!

 

[koda2000]

I'm a big fan of K-Seal, but when plastic tank rads start leaking you should plan on replacing them. What usually happens is that the end seals start leaking and nothing will stop that. Rad shops used to replace the end seals, but they don't anymore. It's not worth the money and I've also seen the plastic tanks crack (no fixing that). I've replace the radiators in all my Explorers/Mountaineers. The V8's are a pain to replace, but the V6's are a piece of cake. I usually buy CSF brand radiators, They're usually around $100-120 if you shop around. They look and fit like OE. I've only had one go bad at just under 12 months and it was replaced (actually refunded) after I found a brand new V6 rad on CL for $75, so I figure I was paid $25 for the labor of replacing it.

Many here insist you buy dual core or all-aluminum replacement rads, but I've never had any issues using the single cores. Most of my trucks came with single core rad's from the factory and now have over 200,000+ miles, so I figure good enough.