Coolant Leak SOHC

[prayforsurf0]

Is there a few common locations to find a coolant leak on a 98' SOHC ? I have a leak that I haven't been able to trace up to the source. It drips down to the road on the passenger side towards the front of the engine. It hits the cross member, and it hits the oil pan in the front so that it rolls back and drips from the back of the oil pan too. Once it leaks enough, it seems to stop when the coolant level goes below the leak.

BTW Koda, if you read this you were absolutely right. That "Timing Chain Noise" I was wondering about and started a thread on was in fact the coolant level too low and sloshing around on start up. When I filled the radiator up the start up noise stopped. But of course now I leak all my fluid out until I the coolant level passes the leak point.

 

[BrooklynBay]

Connect a cooling system pressure tester to locate the source of the leak.

 

[koda2000]

A common place for SOHC engines to leak coolant is from the plastic thermostat housing. They tend to crack at the lower housing, they also tend to leak from where the coolant sensor and sender screw in. Later models use push-in sensors/senders.

I recall telling you about adding water to the radiator, but I don't recall if that included a conversation regarding radiator tank leaks, which are also pretty common on high mileage radiators. There's a plastic cover over the bottom of the radiator. It bolts to the frame with four 10 mm bolts and 2 push-in clips. It's easy to remove. It allows you to see of the radiator has been leaking.

Of the two possible leak sources, the radiator is actually easier to replace.

 

[prayforsurf0]

Connect a cooling system pressure tester to locate the source of the leak.

A common place for SOHC engines to leak coolant is from the plastic thermostat housing. They tend to crack at the lower housing, they also tend to leak from where the coolant sensor and senser screw in. Later models use push-in sensors/senders.

I recall telling you about adding water to the radiator, but I don't recall if that included a conversation regarding radiator tank leaks, which are also pretty common on high mileage radiators. There's a plastic cover over the bottom of the radiator. It bolts to the frame with four 10 mm bolts and 2 push-in clips. It's easy to remove. It allows you to see of the radiator has been leaking.

Of the two possible leak sources, the radiator is actually easier to replace.

Thank you BrooklynBay I will have to do that if I don't figure it out visually.

I don't believe I'm leaking from the thermostat housing as I just replaced the thermostat and didnt notice any cracks. I will have to check again carefully. Thank you again Koda for your help, I'll also be removing that plastic cover and checking the radiator.

 

[swshawaii]

All in on this one. Here's the OEM lower t-stat housing upgrade koda is speaking of. AVOID using aftermarket kits such as Dorman,
Four Seasons, etc., if possible. Gates kit is new, but haven't heard feedback yet, and Gates still uses failure prone threaded sensors.

4.0 SOHC plastic thermostat housing | Ford Explorer and Ford Ranger Forums

http://www.rockauto.com/en/catalog/ford,1998,explorer,4.0l+v6+sohc,1304413,cooling+system,thermostat+housing+/+water+outlet,10337?a=Referer+www.google.com+URL+/

 

[Tech By Trade]

The tanks on the rads crack all the time too. The seam where the plastic meets the metal.

 

[koda2000]

The tanks on the rads crack all the time too. The seam where the plastic meets the metal.

Well, whether the seals leak or the plastic cracks, the result is the same - a new radiator. If you remove the cover from the bottom of the rad and there's antifreeze in it (or signs that antifreeze has leaked in it) the rad is leaking. Don't waste any money trying to fix it. It needs to be replaced, which is a piece of cake on the V6's.

 

[RandomNerd2000]

To add to what Koda said, I had a cap go bad on my 99 5.0, looked like the radiator leaking, swapped back the stock cap it came with, and the leak went away, and to this day, it's holding coolant.

 

[prayforsurf0]

Thanks everyone for the input. I've been waiting for the weather to clear before checking on this issue. I've been anxious about it so I ordered all the necessary parts and sensors to do the lower thermostat housing upgrade, I can return the parts, but I may install anyway.

 

[prayforsurf0]

Finally got a good day to get out and check under the hood again. Thank you to everyone for your input and help. This forum is a lifesaver and has been helping me keep my old girl on the road for miles longer.

I didn't have a coolant system pressure tester so I just used an at home compressor. Warning: Anyone who does the same , do not over pressurize the system. Make sure you have an accurate pressure gauge and set it to 15 psi (I've read you can use a little more pressure than that, but if there is a leak then you only need a couple of psi to hear the air or coolant escaping, do not create more problems by over pressurizing).

With a little bit of pressure in the system I could hear the wheezing sound of air slipping between a crack that was coming from the thermostat housing area. Glad I took a gamble and already ordered all the parts for the upgrade already.

 

[RandomNerd2000]

Be sure to do your radiator cap too, and go with a Motorcraft, I didn't on my 01 the first time, and had weird issues with the pressure in my system once it was properly sealed, and the cap was the problem, both my Explorers have had issues with the cheap parts store caps, my 5.0 poured when I got it if you filled it full, and the cap was leaking through the center "pin"