Another Coolant Leak Question

First -- I did a search about this, but I have some very specific questions. There are MANY posts on the topic, but still couldn't find something specific.

I have a 1997 4.0L with msyterious disappearing coolant.

Reasons it IS a cracked head or head gasket:

1. I can not find a leak anywhere and I looked hard. Checked the hoses and they were old, but did not seem to be leaking. Water pump is about 4-5 years old and was hard to check, but I saw no evidence of stuff coming out of the weep hole. Again, however, it was hard to check.

2. Removed the radiator cap and there was some brown swirly stuff in it. Fluid was not, however, very thick.

Reasons it is NOT a cracked head or head gasket:

1. My year (1997) isn't famous for cracked heads.

2. Runs fine, never overheated, well cared for, and the motor has a reputation for going well over 200k miles.

3. No low oil pressure. Goes a little (not much) over 40 on startup, warmup, and acceleration. Drops to about 20 sitting at a stoplight after warm --- a little low, but I have read on here that this is within normal operating parameters.

4. After removing the undercarriage splash guard, there was some greenish, yellowish dried stuff toward the very front of the engine on the passenger side.

5. Oil looks good on the dipstick and doesn't seem strange looking through the fill cap. I just recently dropped in Royal Purple and did not notic anything odd about the stuff coming out. At that time, I was not really looking either. However, RP is expensive and I don't want to drain it unless this is the only way to check.

Other odd things:

I can hear water gurgling, everytime I shut the motor off.

I can smell very slightly coolant and only sometimes under the hood. I am afraid I am just hoping too hard to smell it and it may be my imagination.

What do you guys think? I just did the valve cover gasket about 6 months ago. I bought the expensive gasket and am not excited about removing the valve cover. Isn't there some chemical test for oil in the coolant so I could see what the brown swirly stuff was?

Sorry for the long post, but I am more and more convinced I will be replacing the head soon. If so, I may replace the whole engine. It would bug me to no end to now that the lower end had received extra wear from coolant contaminated oil.

Hmm... No sign of a leak. How much coolant is it using ?? How many miles on the engine?

Since theres no sign of a leak,two choices:

Blown head gasket burning it. Pull and check all the spark plugs you will see signs on the plug.

Blown head gasket dumping it in the crankcase.. Take a clean drain pan and remove the drain plug if theres coolant and water in the pan it will come out first because the oil is lighter and floats on top. If you use a clean pan and theres no sign of coolant you can reuse the oil.

Good Luck

Nick

Thanks, Nick. I will try those things. I can only guess how much it is using. One-half quart per week maybe? I have 148K on the engine. Also, what would I be looking for on the sparkplug? I guess I have to check all of them.

Wow only 148,000... I'd even try getting a coolant pressure tester(most auto places loan them ) Pressure test the system... I've had some pretty strange leaks that didn't show up till I pressure checked the system..
Spark plugs can show signs of many things. Yeah check them all and compare. There should be spark plug pics. in your service manuel.

Just a process of elimination.

Nick

javajeep said:

Thanks, Nick. I will try those things. I can only guess how much it is using. One-half quart per week maybe? I have 148K on the engine. Also, what would I be looking for on the sparkplug? I guess I have to check all of them.

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Check all of them.

I've torn down engines that have had blown head gaskets causing coolant leaks into the chambers - what ends up happening is that the coolant gets into the chamber and literally steam-cleans the surfaces - you'll see one or two plugs that are cleaner than the rest.

Normal deposits on spark plugs are a sort of neutral ash grey - if you're seeing one or two plugs that look absolutely clean, you've found your coolant leak.

Had a radiator hose spring a pinhole size leak - kind of a mist spray ONLY when fully heated up. Might change rad hoses if they are about due anyway. (save the old ones for spares if ok) First-Pressure test both cold AND hot condition?

Good Luck,
o

orange said:

Had a radiator hose spring a pinhole size leak - kind of a mist spray ONLY when fully heated up. Might change rad hoses if they are about due anyway. (save the old ones for spares if ok) First-Pressure test both cold AND hot condition?

Good Luck,
o

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Often (but not always) you can spot this sort of leak by finding a patch of white residue on the surface of the hose at/around the leak.

Your eyes and your ears are your greatest tools when troubleshooting...

could also be in at the heater core. Did you check that? Although you might smell it more hten once in a while, sitll worth a shot.

GinisKratos said:

could also be in at the heater core. Did you check that? Although you might smell it more hten once in a while, sitll worth a shot.

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I'd forgotten about that! Probably because I don't want to think about a heater core failure - the last one of those I had was a 1974 Datsun pickup that decided to blow the heater core on a hot summer day (I think it was 100*F or better) in a rather dramatic fashion - all over my right leg! Ouch...

Thanks for all the help everyone. The problem with checking the plugs is that I changed them about 5k miles ago -- maybe a little less. Also, put in a new distributer and wires from from Summit. So -- I would expect all the plugs to be clean. I will check them anyway.

I am usually a DIY guy, but I hate collecting and disposing of coolant. Hoses definately need replacing. Don't you have to remove the dash for the heater core? I did the A/C thing about two years ago and paid big time bucks for that. There does not seem to be any smell or water inside the cabin. I hope that is not it.

Can you believe that I am actually hoping for a radiator leak? I found a place on the rad -- passenger side seam -- with a little yellowish/greenish discoloration. I am thinking GREAT! However, I had just driven the vehicle -- the engine was hot -- and that spot was dry as a bone. So -- maybe that is not it.

Yeah, heater core is a PITA. Dash removal required. But you would have strong smell and usually steam on windshield. In Arkansas for the summer, you could probably even bypass your heater core to eliminate that, but I wouldn't if you don't smell antifreeze inside. If you can get your hands on a coolant system pressure tester, it really helps because you can get up close to things without the motor running. Then, if you run it and the gage fluctuates, it indicates a head gasket leak.

Radiator tank to core seam is a common place for leakage. Sometimes you can even crimp the tank on a little tighter with vise grips.

I hope this is resolved -- thanks to all the good people on this board. Went to Autozone and rented their pressure tester. Pumped it up to 17-19 pounds. The FSM recommends 18, but it is difficult to be that precise with the pump.

In any case, the upper hose began leaking a lot, but the pressure was also probably higher than normal. I don't think it was leaking before.

However, the seam on the passenger side reminded me of a tire with a small hole making gurgling bubbles up and down the seam.

I hope this is it. I am fully aware that the extra pressure on this may have created new problems (e.g., leaking out of the upper rad hose), but the pressure never got above 19psi and probably not above 18. However, I am thinking that nothing is wrong with the engine and breathing a cautious sigh of relief.

Also, I am hoping the brown swirly stuff was rust and there was definately the smell of coolant under the hood very slightly when the engine was hot this morning.

I can get a new rad from radiator barn for $113 shipped. I will give autozone my business for all the new hoses and clamps. As I said previously, the waterpump is about 5 or 6 years old -- probably won't replace it unless some of you can convince me otherwise.

Again -- thanks a lot everyone.

Excellent! Thanks for update.

javajeep said:

I hope this is resolved -- thanks to all the good people on this board. Went to Autozone and rented their pressure tester. Pumped it up to 17-19 pounds. The FSM recommends 18, but it is difficult to be that precise with the pump.

In any case, the upper hose began leaking a lot, but the pressure was also probably higher than normal. I don't think it was leaking before.

However, the seam on the passenger side reminded me of a tire with a small hole making gurgling bubbles up and down the seam.

I hope this is it. I am fully aware that the extra pressure on this may have created new problems (e.g., leaking out of the upper rad hose), but the pressure never got above 19psi and probably not above 18. However, I am thinking that nothing is wrong with the engine and breathing a cautious sigh of relief.

Also, I am hoping the brown swirly stuff was rust and there was definately the smell of coolant under the hood very slightly when the engine was hot this morning.

I can get a new rad from radiator barn for $113 shipped. I will give autozone my business for all the new hoses and clamps. As I said previously, the waterpump is about 5 or 6 years old -- probably won't replace it unless some of you can convince me otherwise.

Again -- thanks a lot everyone.

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Cooling systems are usually set up for 13-16psig, if I test them I'll usually test to 20-25 (a test should be harder to pass than normal service, y'ask me.)

But, it sounds as though you're on track.

Helpful Hint - Most radiator shops will take your used coolant gratis. They put it in a big bin, and the recycling truck shows up at intervals. The truck sucks the coolant out of the bin, filters out the solids, filters out the dissolved solids (metals and such,) refreshes the additives, and then gives the coolant back to the shop as refreshed premix - so they don't mind getting more. I can think of three or four shops around here that will take it off your hands no problem. Look in your telephone book under "Automotive - Cooling Service" or "Automotive - Air Conditioning" for leads.

Seems like the expected life of a water pump is right about 5-6 years, and that would be normal driving/use. How well the coolant/system has been maintained could shorten the life.

Joe Peters -- You are right and I will be doing the waterpump and the serpentine belt. I may as well do the belt while I have easy access and lots of room.

5-90 --- thanks for the hint on the cooling shop. I will probably take my coolant to the community recycling center. I have taken it there before. However, it seems nearly impossible to do this job without spilling some coolant. I hate pouring coolant in the water supply and avoid it as much as I can. If this were a flush and fill, I would probably take it to a shop. However, with all this work, I will be doing it at home and cursing with every inevitable spilled drop.

Not to change topics too much, but I also change my own oil. I had two bad experiences at the quickie-oil shops and I like to put in good stuff. That is why I HATE the horizontal oil filter. I can not do this job cleanly. I read on this board somewhere that someone wrapped their oil filter in a plastic grocery bag before completely removing it. I have tried that several times with only limited success.

I know this seems odd - but you may also want to check with your local water company. Many water companies allow small amounts of certain automotive fluids to actually be poured into the drains, and they will get treated there! If I do a small coolant job, I know that I can pour up to a gallon of used coolant in the drain in the garage, and SJWC can handle it. But, I try to catch as much as possible to take in for recycling anyhow.

I am informed that the block drain plug (driver's side of engine block, behind exhaust header) is threaded 3/8" NPT - but haven't verified yet. The plug requires a square drive tool, either 5/16" or 8m/m (which can be made quite easily from a cheap 5/16" or 8m/m hex key - I had to make a couple for those damned Peugeot gearboxes I was saddled with...) I intend to install a drain valve in that hole when I get a chance, and a tube extension to control the draining of coolant. Will write up and report when I get the chance to do so.

For the oil filter, I also plan to install a remote oil filter mount, with the filter hung "pendant style" (open end up.) This will allow for greater control of the oil when removing the filter, and I will be able to pour the filter full before I install it (thus helping to cut down on "dry time" on startup.) I know the RENIX oil filter nipple is M20-1.5, and I believe the HO is 7/8"-14 or 7/8"-18 (I'd have to check.) I'm not sure what the block thread is - have to check that, but I'd like to be able to just do away with the whole elbow adapter entirely if I get a chance.

Most of the "quickie-change" shops around here use Pennzoil - which I flatly refuse to use in a two-stroke! And, I wouldn't trust most of those guys in a public loo without a "Don't Eat the Big White Mint" sign, from what I've seen...

I am reviving this thread and I may start a new one if people are tired of this one.

I changed the radiator, water pump, all hoses (including heater hoses), and serpentine belt last night.

A few questions.

First, I drained some coolant into a tank using the petcock valve. Not much came out.

Second, I tried and failed to loosen the block drain plug. That was a bugger to get to and I didn't have the correct tool. At refill, it took nearly all of two gallons. I guess this means that there is still a gallon of old stuff in there? Isn't capacity three gallons?

Third, I created a toxic waste superfund site when I pulled the lower hose. Coolant went everywhere and my huge catch basin was not adequate to get it all. I hope all goes well with this job. I plan on changing the coolant once per year at a shop from now on just so that they can deal with coolant. I hate seeing that toxic crap go down my driveway.

Everything seemed to go well. I scraped gasket material for a long time and hope that I got it all. I sprayed the new gasket with permatex and adhered it to the new pump before mounting.

During the mounting, I forgot to put the fan shroud in and tried to put it in with the new rad mounted. That was a mistake. Some of the fins got crushed (about the size of a quarter, but there does not seem to be a leak. Still it bothers me a lot. I took the rad out, put in the shroud, and remounted the rad with no problem.

It was late at night as the job was coming to an end, so I elected to not change the thermostat and the water outlet gasket.

Anyone worried about this, especially the crushed fins, my inability to drain the block, or not changing the thermostat and water outlet gasket? Thanks.

You can buy a fin straightening tool at most chain auto parts stores, or harbor freight.

I wouldn't get to worried about a quarter sized area of the fins.

Just my humble opinion, but I would say 90% of the cars on the road have never had the block drain plug removed. That said, it would be nice to do it, and some here have installed drain valves instead of the plug.

I have never pulled a block plug on my own vehicles, but I flush the system and put in new coolant annually.