I have a 95 Aerostar with a 4.0L engine. The coolant level is consistantly low. There is no obvious leak, like none dripping out of the bottom. It's almost like it's evaporating. I just replaced the radiator cap and I filled the overflow tank to the cold fill line. I actually may have filled it I little higher because the level is hard to see. (Is that a problem?) Sometimes you can smell a faint coolant smell. Last night I went out and topped the radiator off and this morning it was low again. Could that just be air bleeding out of the system? Any other things I should check?

Thanks for your help.

 

The only way to find mistery coolant miss is the pressure test. I belive you can do it....

 

Where do you smell the coolant? It may be a a very slow leak. Try Pablo's suggestion of a pressure test. You can check with one of your local auto parts store to see if any one of them will loan you a pressure tester. Since these attach to the radiator fill opening, you want to make sure you don't pump it up past about 16 psi, or you could make a new leak.

 

do you get moisture buildup on the inside of the windshield on cool morning, more than normal for a vehicle?
indicates heater core leak, common in aeros

how old is your radiator cap? any splits or cracks in either seal on it?

filling the coolant overflow tank much beyond the line in hot climates or towing will cause overflow of the OF tank.

if pressure testing doesn't pinpoint the problem, add a UV dye to coolant and use a black light on the oil, around heater, on coolant and heater hoses for pin hole leak, on exhaust tail pipe and on inside of windshield

 

I have a 96 4.0, 133,000 miles. Bought it with 30000 miles. I've had 2 experiences I'll pass on. From day 1 of ownership it seemed to lose fluid but never a sign of leakage and it pressure tested good at the dealership, nothing seemed to come out of the exhaust and no discoloration of antifreeze. After many miles of adding a little every now and then I somehow came to the conclusion the overflow hose had dried out and had a small crack in it. I flipped the hose around so the cracked end was in the overflow tank, submerged. No more problem that I was aware of.

Then at 100,000 miles or so, while I was crawling under the van for some other reason, I noticed just the faintest green discoloration and maybe a small drop or 2 of anti-freeze at the bottom of the tank right where the tubes meet the tank. Pulled it off brought it to the radiator repair. He pressured it up in a water vat and got a small amount of air leakage and then it stopped. No more air leakage. I went ahead and replaced it anyway. My take was that there was probably some kind of deposit of hardness at that point and after 100000 miles it corroded thru the tube as a pinhole leak, but the deposit was keeping it from leaking consistently. Eventually I figured it would blow out as a hole. I had seen similar under-deposit cprrosion on industrial exchangers I had the pleasure (or displeasure) of working on. I would inspect as thoroughly as possible looking for a sign of leakage (discoloration or scaly looking deposit) and maybe not a full blown leak at the tank bottom. For what it's worth...........

 

Becca,

Look behind your air cleaner housing behind your passenger side head-light. You will see a plastic heater valve (black plastic) that the heater hoses connect to in the front and then exit out the rear of it. This same item also has a small rubber hose connecting to it on the bottom. Do you see it? If this is bad it will leak out just a little bit of coolant out enough to drive you crazy.

If this is wet at all the plastic housing has cracked. Either get a new one or suppliment it with a couple of metal tube replacements and just clamp it to your heater hoses. It won't make any difference to do this as long as you close off the hose.

 

There are freeze out plugs on the motor that may be a little porus. Particularly the two on the block rear. You can check these by removing the inside cover and exposing the engine rear.

 

What roree said is a very good choice. Just remember though. If you remove the "DOG HOUSE" and then look around-and when you're done make sure that the dog house is "SEATED" correctly back into position. How can you tell? As you are removing the dog house you should be able to notice a type of "SPRING ACTION" happen in your hand as you are unlatching the clasps. Going back into the lock position when you are done should be of the same tension. Anymore than first noticed means you have it in a bind
Do you see the rubber seal under it? It will need to go back on "EXACTLY" the same way.

I reinstalled mine one time and I had (what I thought I had) was an exhaust leak going into the cab of the van or worse yet some sort of a fuel leak. I actually drove it for a couple of weeks like this. (Look at an earlier post of mine-I think one of my original ones-you'll see my delima). I had it incorrectly seated/reinstalled.

There are two more ways to see the rear of the engine/block as well. With the wheels turned at an angle you can peer into the wheel well and see just over the frame and to the rear. If that isn't possible jack up the body and shimmy behind the wheels and under the car. You can look up with a flash light and then tell. If you see more than the "GRAY" color of the block and what looks to be rust-don't take chances-have them replaced.

Let us know what you find out okay?---Have a good one--Boz

 

Had plug in head leaking. was diffcult to find becouse of coil

 

Just to remind everyone, the 4 liter engine does not have coolant plugs in the back of the block. Even if it did, you would not be able to see them without removing the transmission. But removing the dog house cover will let you see the coolant plugs on the back of the heads.

 

yeah! Xlt4WD90 is right! 3.0 has, 4.0 does not and it is good. Less hedache