Coolant Leak

[Triton46]

My coolant is disappearing from the recovery tank. Its not leaking from the radiator (new) and there is no fluid on the ground or in the car.

I figure it is going into the engine, but where? I looked in the oil cap for moisture/foam but saw none.

 

[JDraper]

How long ago did you put the radiator in?? If you didn't get it full when you installed it, it could be the water being sucked back into the radiator as the motor cools.

It's also possible you could have a leak between your water jacket an a cylinder. That wouldn't necessarily put water into your oil. A compression check could verify that. Another way to do a quick check is to take the cap off of your radiator (when it's cold ), make sure it's full of water, and then start the motor. If you have a compression leak to the water jacket, you should get water or air bubbles being pushed up out of the radiator.

 

[Triton46]

How bad is that and will it get worse? I put in the radiator about a year ago (thanks again by the way ). Initially it had some air in the radiator, but it stayed at the cool level (when cold) after putting more coolant in the reservoir.

If it is the water jacket, what needs to be done to fix it?

 

[JDraper]

It's also possible you water pump is leaking, or you have a pinhole somewhere in the radiator (I hope not!!) or the hoses that only leaks when the system is hot. I'd do a real close inspection of the motor for water leaks before coming to any conclusions.

If you are getting water into the combustion chamber, it could be one of several things, all of which are NOT good. I'm not 100% up on exactly where the coolant circulates on a 4.0, but in general, the following places are usually suspect:

1. Head Gasket
2. Intake Manifold Gasket
3. Warped Head
4. Cracked Block

Some motors circulate water through the intake manifold, and some don't. I don't have my book with me to check on the 4.0. Maybe someone else here who has ripped a 4.0 apart has that info.

BTW, I just helped a friend fix the same problem on his Escort GT, and he had a blown head gasket, a cracked head, and a bad water pump!! We think the water pump went first, overheated the motor, warped and cracked the head, and blew the gasket. Cost about $450 in parts for a rebuilt head, gasket set, timing belt and water pump.

 

[Triton46]

Thanks Jeff.

I don't think I have a warped head or a cracked block. I know the lower manifold gasket has a leak (oil) so maybe this is the culprit.

I plan on checking/replacing the hoses soon so hopefully that will alleviate the problem.

I had planned on doing a rebuild at 200k, should the leak get worse and I pinpoint it to a gasket leaking into the cylinder...should I plan on having the rebuild done then?

 

[spiper]

I had a similar coolant leak problem. I was losing all most all of my coolant every week and a half. I finally found a small hole in the passenger side heater hose off the heater core. It goes down under and you cant see it except for crawling underneath. I never could find it cold only after it warmed up with the heat on and after the thermostat was open.

 

[Triton46]

where can you get a cylinder compression guage?

Is it as simple as plugging into the spark plug hole and starting the engine?

 

[JDraper]

You can get a compression gauge at about any auto parts store. The way to do a proper compression test is to remove all the plugs, disconnect the fuel pump (you can do that by pulling a fuse or tripping the inertia switch), disconnect the coil, and then screw your gauge into the spark plug opening. Crank the motor over a couple about 10 revs, and read the gauge. Continue on until all cylinders are done, recording the readings as you go. After you are done compare the readings. If two adjacent cylinders are low, you probably have a leak between the cylinders. If one is down, then the likelihood for a blown gasket is high. After you do this test, you then put a couple of squirts of oil in each cylinder and re-do the test. If the compression values are significantly higher, the rings are worn.

For the 4.0OHV motor, spec is a minimum of 101psi per cylinder. The tolerance is about 25% cylinder to cylinder, eg if you min psi in one cylinder is 101, the max in another is 134. If the min in one cylinder is 150, the max in another is 200, etc.

 

[Triton46]

Thanks Jeff

Will be checking sometime this week.

 

[Triton46]

Before doing the compression test I got under the car, after letting it sit for a day, to see if it might be the water pump.

Under the car, I found the leak but am not sure where it is coming from. On the 1991 - 1994, if you are under the front of the car to the front of the front differential but behind the radiator is the oil pan. On the front passenger side corner of the pan, there is a puddle of accumulated antifreeze. It is adhearing to the bolt and some sludge. It is either coming out of the pan or from somewhere above. I beleive it is coming from above, but where? Does the 91 have a weep hole? My book says some early models do not.

 

[Rhett]

Maybe the coolant you see there is getting blown backwards. In other words, the leak may be up where the rad is, but when you are driving the coolant gets blown back some toward the engine. That makes it hard to tell exactly where the leak is.

 

[jshexplo96]

I was having the same problem and i found my culprit to be the heater diverter valve.....located passenger side of engine bay. Black plastic piece with two hoses in and one hose out.....it supposedly opens and closes....well mine was leaking....if that is it you should be able to smell the coolant burning a little on the exaust.

 

[Triton46]

I beleive the leak is coming from the heater in/water pump out hose at the water pump itself. I could feel no leak on top of the bolt although it appeard to be coming from the bolt.

Upon further inspection, there seems to be some leakage around the hose on the water pump (to the heater) which may be blown back by the fan.

I am replacing that hose this weekend. I will also check the heater diverter. Is it near the water pump on the front? How big are the hoses going into it?

 

[Ross-N-Chicago]

91s dont have a heater diverter or valve. I had the same leak, couldnt tell from where so I replaced the water pump and all heater and cooling hoses for peace of mind. No leaks and took 2 hours to do. I mean, the water pump is so cheap and easy to do why not? And that is one part you do not to see fail. Also retorqued the lower intake for PM. That was a pain.

 

[Triton46]

rossneag,

What is involved in removing/replacing the water pump? It looks like you have to remove the radiator, fan, and about 20 bolts holding the water pump to the engine. I am considering that, just wondering whether or not I want to tackle it on my own.

I'm like you though, its cheap insurance and it will be going some day....soon!

 

[Ross-N-Chicago]

Triton,

Here's what you need and what I did.

Water pump from Murray's, $30. Copper RTV from Permatex, $4. New hoses all over, $15. Clutch/Fan removal tool on loan, $35 (MUST HAVE THIS TOOL TO DO). I drained my coolant and reused since new. Just follow the Haynes for water pump replacement and all should be fine. The hardest part is getting the fan off and scraping the old gasket off. Ford used a crappy paper gasket and guess what comes with the new pump, paper!! That's why I would use the better RTV, put a good bead on both sides and you don't have to worry at all.

Its an easy job and with a beer and radio you'll be in and out in 2.5 hours or less at a comfortable pace. Just make sure you let the RTV set up before installing.

PS- And no, you don't have to remove radiator. Haynes manual says the 12 bolts to water pump are different lengths, mine were all the same FYI.

 

[Triton46]

Three questions:

1) Where is Murray's (webaddress)?
2) Where did you get new hoses for $15? Napa is quoting me $20 just for the heater/pump hose that I am replacing this weekend.
3)How much beer?


OK one more, is that a new or remanufactured pump?

 

[TSTONE]

murry's discount auto parts is the name, kinda like a napa etc...

as for online you might www.discountautoparts.com they usually have good prices on that kind stuff

 

[Ross-N-Chicago]

Heater hoses are 5/8 ID I believe. You can get 10 feet and just cut to size. A couple beers, depending upon your size and ability. I was driving later so I restrained myself (to all of you, I never D & D). And I bought a remanufctured pump. But guess what, it was a Ford original that was sandblasted and painted and new pump blade. Still had warranty on it too for 12/12,000 I think.

 

[Triton46]

Excellent, thanks!

Is there any room for improving cooling efficiency here?