Losing coolant somewhere

This problem has started in the past month. the coolant was a little low so I added to the full mark. About a week later, low again. This is unusual for my car to be doing this as in the past I have not had to add coolant more than about once a month or less. Now, it is every couple hundred miles I have to add about a pint.

The usual suspects such as water pump, no puddles on the ground or on the motor. The heater core has in the past put smells into the car to let me know it was lealing. No hoses leaking that I can find. I am thinking it must be the head gasket.

I have had some oil leaking external to the head below the exhaust manifold for years. That seems to have reduced somewhat in recent weeks. If the coolant is leaking into the engine, it is such low quantity that I do not see a cloud of vapor from the exhaust.

Any suggestions of other places to look?

Bob in Lake Havasu

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Bob in Everett
This problem has started in the past month. the coolant was a little low so I added to the full mark. About a week later, low again. This is unusual for my car to be doing this as in the past I have not had to add coolant more than about once a month or less. Now, it is every couple hundred miles I have to add about a pint.

The usual suspects such as water pump, no puddles on the ground or on the motor. The heater core has in the past put smells into the car to let me know it was lealing. No hoses leaking that I can find. I am thinking it must be the head gasket.

I have had some oil leaking external to the head below the exhaust manifold for years. That seems to have reduced somewhat in recent weeks. If the coolant is leaking into the engine, it is such low quantity that I do not see a cloud of vapor from the exhaust.

Any suggestions of other places to look?

Hey Bob- I'd say the first steps are putting a good size piece of cardboard (an unfolded box works well) under as much of the motor and radator and surrounding area as possible. Make sure it's under there all the time and you check it after a good running especially. This will at least give you some feedback for external leaks (step one). These leaks take their time showing up.... (again, step one

Also check around the engine and compartment, common places are top of throttle body where those two smaller hoses run in to the warmer thingy and under the intake manifold for heater and various smaller water hoses. You can tie wrap sections of paper towel to suspect areas (it's a great way to find small leaks that get blown dry from road air currents....(still step one

Rick

Thanks for the good suggestions. I have been under the hood this afternoon looking in just those areas but was not able to find any evidence. Making this more perplexing is that my coolant filler cap does not hold pressure so the coolant reservoir and radiator do not have any pressure to force a leak. The water pump will create some with its flow. The water pump was leaking a little for several months but now there is nothing under it or anywhere on the front of the engine like there was before. The water pump leak was pretty small as I only had to add coolant about once a month. If the heater core was leaking again, I would notice as the heater is used most mornings. My concern is that is must be going into the combustion chamber due to a head head gasket but the plugs all look alike so no suspects there. Even the oil leaks from the head gasket have slowed somewhat. Oil consumption does seem to be up though. No steam or smoke from the exhaust that I have noticed. Very frustrating.

Bob in Lake Havasu

That's very suspicious. The system should pressurize.

alan

You may be overthinking this.
If you sat the cap does not hold pressure, then there is your leak!
If you must add so little quantity every month, just keep doing so, and leave it untill something more significant happens.

Get the cap fixed first. Check the spark plugs. Is one of them much cleaner than the rest? Then you might have coolant leaking into the cylinder. But check the cap first.

The cap has not held pressure for the eight years I have owned the car. The rate of fluid loss has been very slow. Mostly when the heater core was leaking. The situation most recent is a much higher loss rate. It could be the heater again but I do not notice any smell from it like it has in the past when it was leaking. Also does not fog the window on the defrost setting.

That reminds me, I need to check it again as I drove for a couple of hours today.

Bob in Lake Havasu

OK. Still the first step: replace the cap. Your system needs pressure. When under pressure, the boiling point of your coolant rises. Luckily, you don't live in California, otherwise it wouldn't have held up for 8 years.

I agree with you but I have driven it to California via San Jaquine valley at 108 ambient with aC runnning and did not lose that much coolant. I was watching it very carefully and checking it at every stop along the way. My thermostat is only a 180 deg. so it does not press far into the boiling range. Since I watch this kind of thing carefully and do all my own maintenance, I am not worried about the temp with low pressure. I inspected the water pump impeller for cavitation damage when I changed it each time and observed none. There are a couple of concerns I do have with it and one is the water pump seal. Without pressure, it could get dry from the heat and damage it so it would leak prematurely...which it seems to do. Also the heater core was leaking a little and I was also checking the fluid level to be sure that did not cause a problem. Even that was not the rate I have now. I am beginning to think my new one is leaking but do not get a smell out of it like I did before. Do not see any on the ground under the car either. Still perplexed.

Bob in Lake Havasu

Bob, you did say you pressure tested the system, right? If you removed the cap on the plastic tank on the passenger side and used that as your connection point for the pressure tester and the system wouldn't pressurize, that kinda takes the cap out of the equation, right?

alan

You have two problems from what I've read. You mention you used to have a "small" leak at your water pump but that went away. Second you say your cap doesn't keep pressure in your recovery bottle.

Your small leak at the water pump suggests a eminent failure awaits. You are probably aware of this, but just in case some readers are not, the bearings on the pump wear unevenly from the pressure applied by the belt on one side of the pulley, this allows the impeller shaft to wobble which wears the seals. Keep your ear out for the grinding noise of bearings gone bad and watch that leak if you want to stretch it.

The cap is cheap and why have you waited 8 years (?) to replace it? Get one. What puzzles me is you don't describe your failed cap in the same manner mine failed. My cap wouldn't hold pressure and it was obvious coolant was blowing out of the cap (with bottle properly filled). Check your bottle for cracks, after 20 years or so on the road these plastic bottles develop hairline cracks and can develop a "weeping" leak Again, they aren't expensive and easy to replace. BTW, how old are your radiator hoses?

Meanwhile keep your eyes and ears on that water pump, you don't want to toast your engine.
I think you've diagnosed your problems well. My thoughts on these types of problems is they are easier and cheaper to fix while the problems are small than after you are stranded on the road side because of an over heated engine.

Just want to say I reread all the posts and I wanted to edit a few things, especially the 8 years with a bad cap thing but I guess I'm such a noob on this forum I don't have that privilage. Sorry.

Thanks guys for all the commentary. It gives me more ideas of places to look for the lost fluid. I had not thought about the bottle its self. The main reason I have not replaced the cap is that several hoses on the cooing system are verrrryyy old. Especially the expensive one under the intake manifold that is molded into a four branch cross of some kind. I have perused each with a clean paper towel to see if there are any drips or leaks but still nothing visible. With the volume that goes missing I keep hoping I will see a puddle sometime. Still nothing. I am concerned that it could be the head gasket but no evidence yet. I suppose if I were to pressurize the system with the engine not running and look for evidence that might be more successful. I could put a good cap on and let it pressurize also. Would not want to get too far from home doing that though. Might burst one of the old hoses.

I need to do some repairs of other stuff. Perhaps I should change the head gasket and all those hoses along with my new muffler and transmission seals. Wouldn't it be nice to have a leak free car for a few weeks anyway? If it still leaked it would have to be my nearly new heater. All that would mean several days of sore back and knees though. I take some pride in being able to do most of this kind of stuff on my own car but seems like it is not quite as much fun as it used to be. The old saying about the mechanics car being the one most in need of repair is probably true. I can sympathize with him.

Bob in Lake Havasu

Before you pull your head you should remove and inspect the plugs. If a plug looks like it has been steamed cleaned, it probably was. For years Land Rovers were/are notorious for coolant leaks from poorly installed head gaskets from the factory. Land Rovers techs troubleshoot this by pressurizing the coolant system, make sure it holds pressure, if not find the leaks and finally pull the plugs to look for a wet cylinder. Another way to tell is to just put your finger in the cold coolant. If it doen't feel oily your head gasket is most likely not leaking. And you can check you oil when you change it, if there is water in it you will know it and quite honestly if there was water in your oil your engine would have probably seized up a while ago.

Speaking of coolant hoses, Pelican Parts (One of my go to parts places) is a great place for BMW parts.

On this page they have a hose kit and the notes tab shows every hose included in the kit:
On this page each hose is offered individually:

I changed out all my hoses along with my bottle and cap. I found this job easier than it looks and wasn't hard on my 'ol back and knees.
I know what you mean about working on cars isn't as much fun as it used to be. I do as much work on my cars as I reasonably can and I no longer hesitate to pass the car to a good mechanic for big jobs like tranny seals.

I checked the plugs a couple weeks ago and they all looked normal and not steam cleaned. I expected to see one or two that looked different from the rest but they all looked the same to me. It could be the heater but have not noticed the telltale smell of coolant or fog on the window.

Bob in Lake Havasu

Bob, pull the plugs, pressurize the system for 10-15 minutes then crank the engine over with the plug out.

alan

That is one thing I have not tried yet. I was trying to think of a way to put some compressed air into the system and replace the bad cap with one at the correct pressure relief setting.

I have a 1200 mile round trip coming up at the end of the month and need to decide which car to take.

Bob in Lake Havasu

Bob, here is what I think, based on what I have read here so far.
If you are sure that you don't have an external leak, i.e visible puddles on the floor, I believe you may have a head gasket issue, where there is seepage between a cylinder and a water Chanel, however, the water will not be drawn into the engine, hence no vapour out the exhaust and no "steam cleaned" plugs.
Rather, combustion pressure will enter the cooling system, as you have stated, your system does not prassurise due to a faulty cap, so there is no pressure to force the coolant into the cylinder, rather the cylinder pressure will enter the cooling system, probably forcing water out of the cap vent/blow off/overflow/whatever.
Of course this will only happen while you are driving, so once you stop and switch off the car, the water will stop being forced out the cap, hence no puddles, where you park, in fact it may only be escaping as steam, leaving little or no clues.
Try not to think of it as large amounts of water, but rather small amount that is easily evaporated by the heat under the hood.
Just my 2c Zim, for what it is worth.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.

After my trip Memorial week end trip, I decided it has to be the leakage is going into the crankcase somehow. Took the plunge and ordered up the gasket kit and several other parts to change the head gasket. There sure are a lot of parts that have to come off. I have worked on it for about 4 hours already and have just about got the timing belt off. Discovered I probably should change the water pump too as there is a drop of water hanging off the vent on the bottom It is just enough trouble that while I am there it will be worth while to know it is not much of a risk later.

Bob in Lake Havasu

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Bob in Everett
After my trip Memorial week end trip, I decided it has to be the leakage is going into the crankcase somehow. Took the plunge and ordered up the gasket kit and several other parts to change the head gasket. There sure are a lot of parts that have to come off. I have worked on it for about 4 hours already and have just about got the timing belt off. Discovered I probably should change the water pump too as there is a drop of water hanging off the vent on the bottom It is just enough trouble that while I am there it will be worth while to know it is not much of a risk later.

Hope you find the head gasket has leaked otherwise it was the water pump all along.

I had a few minutes of doubt but then took the 710 cap off and glared inside the valve cover for a little while. It appeared to look wierd in there so I pressed on. After I got the valve cover off it was obvious as there is water in the low spots under the rocker arms. I now hope I have not done damage to the crank bearings. Almost afraid to pull the drain plug to see how much water there is there.

Bob in Lake Havasu

Unless the engine has been left to sit for lengthy periods; water in the oil won't hurt anything. It's when it's left too long and the bare metal becomes exposed to air that rust can form.

Water(oxydation aside) is an excellent lubricant!

Also; if the crank case oil doesn't look like milk; you have got at it before any real damage can have occured

Thanks for the encoragement Peter. I have heard that the ethylene glycol is damaging too. There is a few tablespoons full of "mayonaise" in the baffle in the valve cover but the oil never did get the milky look. I would not be surprised to see some water come out when I drain the oil though. The filter will be changed too.

The cylinder walls still have some hone marks showing and there is not an appreciable ridge at the top either. Pretty amazing for a 228,000 mile engine.

One of the neighbor's, a 19 year old came over and asked me about the car as he is considering buying a 1988 E-30 coupe. Even in my distress of having a garage full of parts instead of a car, I offered him encouragement that it was a good idea.

Bob in Lake Havasu

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Bob in Everett
One of the neighbor's, a 19 year old came over and asked me about the car as he is considering buying a 1988 E-30 coupe. Even in my distress of having a garage full of parts instead of a car, I offered him encouragement that it was a good idea.

Priceless!


My old Citroen shows all those symptoms at a mere 200000km, plus horrid oil consumption... So you know how durable BMW were built back in the time...

Good job!

If you haven't replaced the belt tensioner, consider doing so. Our E30 has been sidelined for the past year and a half due to catastrophic head damage due to a broken tensioner.
We had put a really nice rebuilt head in our car but I never considered replacing the belt tensioner. It's about $30.

As I was taking the belts off I noticed that water pump appeared to be leaking slightly so changed it and the idler for the new belt.

Good advice all around.

Bob in Lake Havasu