Losing coolant

[Sdude2008]

1988 ext cab 2.9 with 154k. I guess I pretty much know the answer but I thought someone might give me a new angle to look at my problem. I seem to be losing coolant at a steady rate. I first noticed the coolant level was down several months ago. I was topping it off about every couple weeks at first. I checked for leaks and found some fluid leaking down near the radiator drain plug. I also noticed when I opened the plug nothing would come out. I replaced the radiator. Now I am topping it off every day, it is about two inches down after about two hours of driving. I again checked for leaks and found some fluid dripping from the engine side of the lower rad hose. I tightened the hose and no more drip. Still the fluid level is down every day. This told me what i didn't want to know. To check the oil for water... I drained the oil and no sign of milkshake... However when I pull the filler cap I do see slight traces, like droplets of light brown goop. I don't see any evidence in the radiator itself... Also I checked all hoses while hot and all are warm to touch except the lower hose which is cold... So do I have some kind of blockage? Intake leak? WTF? I need this fixed can't be refilling rad daily... Thanks for any suggestions.

 

[MAKG]

One possibility you haven't checked yet is the rad cap. If it doesn't hold enough pressure, the coolant can boil and push coolant into the overflow.

 

[Sdude2008]

I checked the cap it seems to be ok. I don't see the missing fluid in the reserve... I'm wondering if a dead thermostat could cause a blockage and cause fluid to burn off internally... The cold lower hose makes me think the water pump may not be working... But I do get good hot heat inside... Also I have seen blown headgaskets before the fluid loss is much greater and it usually effects how the engine runs. My truck runs fine. The temp gauge doesn't go above 1/4 or so but yet each day I check and the fluid is down a few inches...

 

[MAKG]

If you get heat, the water pump is working just fine.

A cold lower hose either means the radiator is completely blocked (perhaps by the thermostat), or the radiator is working fantastically. Might be worth pulling off the lower hose to see if anything comes out the radiator (it certainly will come out of the water pump).

You can't "burn off" coolant inside the water jacket. You can boil it, but it has to go somewhere. Which means, the overflow, outside, or into the cylinders or crankcase.

 

[Sdude2008]

Well the radiator is brand new. So I guess I'm looking at a semi-blown head gasket? Just leaking away? Or could a bad intake gasket cause the same problem? That would explain the goo under the oil fill cap... Must be just enough to not effect the engines performance but to run the radiator down... Also no sign on the dip stick or when draining the oil...At this point I wonder if it's worthwhile to attempt to replace the head gasket(s) or just drop another motor in... Great... Thanks.

 

[Sdude2008]

Well I did an hour of reading through threads and it sounds like maybe I have a cracked head... So is there a way to tell without removing them? (sigh) I know the answer will be no... Lay it on me... thanks.

 

[umpire613]

you might try ?

You might try doing a simple compression test, see if you got one cylinger really low, while your at it examine the plugs. see if one is cleaner than the others.. but first make sure your oil doesn't look like a bad milk shake.. water in the oil.. NO GOOD ! if it's just the gaskets, some new head bolts, might as well change the thermo while your in there.. if your really upto it a new water pump.. but at least have the heads checked if you don't see anything wrong with the gaskets.
your not seeing any excess steam or smoke from the tail pipe are you.. that could be a bad gasket and or head.. it's a good afternoons work.. if you have every thing around.. good luck sorry just saw you had checked the oil.. but keep an eye on it ! water and oil.. ruin crank bearings very quickly... then it is over haul city..

 

[MAKG]

The most reliable test is a leakdown test. Pressurize each cylinder at TDC/compression to 100 PSI, with the rad cap removed. Bubbles in the radiator neck = bad.

 

[90B24wd]

I'd also check the heater core. All 3 Bronco II's that I bought had cracked heads, and I know why! They all had leaking heater cores.

 

[Tedybear]

I'd also check the heater core. All 3 Bronco II's that I bought had cracked heads, and I know why! They all had leaking heater cores.

We must have the oddball one. Both heads where cracked...but the heater core? Looks good and doesn't leak (yet LOL)

S-

 

[Sdude2008]

Update. I replaced the heater core about six months ago... Today I popped my radiator cap (lev-r vent cap) after driving for about two hours. Lately I have been able to do this with no problem because the fluid is low and I am able to refill... Well today the pressure blew some fluid out and it was cold... Cold fluid???? After running the engine that long? OK what the heck am I looking at here? Is my thermostat stuck shut? I do get heat but I think it may have been a little cooler than normal today... Any more suggestions? Thanks.

 

[MAKG]

Sounds more like a thermostat stuck OPEN to me.

If it's stuck closed, it will pressurize due to coolant boiling.

There should still be pressure under the cap if there is ANY coolant in the block.

So, in addition to everything else, you still have a leak.

 

[bardat]

I had a similar problem on my 88 ranger, it was corrosion around the thermostat housing. There were several deep pits in the intake manifold. It was dripping off the bottom of the housing, which was hard to see, then ran along the motor to drip off much lower. I custom cut a "O" shaped cork gasket for behind the thermostat rubber ring, and cut a triangle for the thermostat housing to intake as well. I haven't lost coolant since.

 

[The Fox]

Mine has a similar problem, but it is I have no cap on the overflow tank. I see that coolant is always around the tank where it has sloshed out.
Nick

 

[Sdude2008]

Yes there was pressure under the cap when I opened it and the cold coolant blew out... I'll pull the thermostat housing to see what I can find. I read on here someone put dye in the coolant to help trace a leak. What type of dye and/or where would I get some? Thanks to all who have replied.