My L98 is using water, and Im having a hard time tracking down why. Sorry for the length, but I have to go through what Ive already done. First I had a busted crimped hose clamp on my oil cooler line where I was leaking. The hose had gradually failed and fouled the stock clamp, it was split wide open. Replaced the hose, and put a screw down clamp on in, which Im not satisfied with, I want a better clamp. Theres a little dampness there at the bottom of the hose sometimes where it meets the metal line, but not enough to account for the amount of water Im losing. Last week when I got to work there was a puddle of water under the car by lunchtime. Thoght it was the oil cooler line again, but no, the heater control valve was leaking like a siv, so I replaced that too. Not leaking now that I know of, but I drove it 88 miles yesterday, and had to put probably 36 oz of water back in it to top it off!

Next worry is head gasket, so heres what I did. Spark plugs all looked ok, greyish tan residue on them. No smoke in the exhaust, no water in the exhaust, ulness it sits for a long time at idle and it drips a little with condensation, but thats pretty normal isnt it? The car does not run hot. Rarely cracks even 200, in fact, I wish it would run hotter. Drained the oil, five qts in, five qts out--no water in the oil, no water on the dipstick or under the oil cap. Tested the oil by dripping it on a hot stove, it smoked did not sizzle. Although, the dipstick always shows that its a little too full, even immediately after you do an oil change. Next I did a pressure test. Pumped up to 15 lbs, and it took 7 minutes for it to bleed down to 14 lbs. I wasnt satisfied, so two days later I tested it again, and sat there twiddling my thumbs for 10 minutes while the needle did not budge one bit off 15 lbs. Ive also run the motor and looked for leaks and havent seen one. The radiator looks ok, in fact it looks so good Im thinking its probably not OE.

But heres another wierd thing. Earlier this summer it was using water, but you could tell by looking at the dropping level in the overflow tank. Now you have to open the radiator to look. Its not drawing from the tank as it uses, when it did before! The level drops in the radiator, and the tank stays the same. Btw, the hose to the tank and the opening at the cap are both totally clear. Does that mean its not building up enough pressure to open the overflow port? If not, why?

Oh yeah, one more thing. I did crank compression tests on all cylinders (Im at 155k miles) Most ranged from a solid 190-170 except number 4. It was at 158, but these were dry numbers--I have not done a wet test. But the plug looked totally normal. So where is my water going? Intake manifold gasket problem? What? Im getting sick of chasing this! My inexperience may be causing me to overlook something. Help!

 

Intake gasket, water pump bearings, the fitting at the back of the intake pass side that goes to the heater, radiator, ....

Might want to get some of that UV dye stuff and the flashlight and all that that goes with it. That'll find it right away. Don't forget to use it on the oil. (which would indicate intake gasket, NOT likely to be head gasket)

 

The water pump is fairly new, and Ive looked for evidence of leakage at the firewall where the heater core is, no dice. Btw, I forgot to mention, I have a new heater core too. But that fitting at the back of the intake, hmm, thats a good one. Forgot about that. Im liking the intake gasket theory, like it a lot better than head gasket. Can I get the dye at Autozone etc.? Ive never used it before, I'll have to look it up.

 

Oh yeah, heres one more thing. There is a very small oil leak thats coming from somewhere above the oil filter. It runs down the side in the #'s 5 and 7 area, onto the oil cooler, then down to the filter. The drip never falls off, it just sits there. LOL No, or very little dripping in the driveway. I cant tell where its coming from. Could be coming from way up at the intake. Guy at Autozone seemed to think I had an intake gasket issue when I told him most of this, but I wanted to hear from the forum too.

 

Having done my first coolant pressure test today, I feel confident on giving some input. (oh boy)

Did you do the pressure test at cold and hot temps?

Did you test the radiator cap?

 

First test was hot, second colder. So the one with the slow leak was the hot test, I'll admit that. And no, I never tested the cap. How do I do that? Btw, these two tests were before I knew the heater control was leaking, if it was leaking then, and it might have been. Oh yeah, this reminds me. The second day I also put the tester on without pumping it up and started the car looking for a quick pressure buildup, there was none. I ran it up to about 170-180 or so and only got a few pounds buildup. So it had run for a few minutes, so the second test was not completely cold. I had forgotten that. After that test, I stopped the engine, pumped it up to 15 and waited. No drop.

 

You probably need an adapter to test the cap. You put the adapter on the pressure tester, put the cap on the adapter and pump it up to the cap's pressure. If it holds pressure, it's good. If the pressure decreases, you need a new cap. You could probably go to an autoparts store and either have them test the cap or rent a tool/adapter.

Now that you've fixed things, do another pressure test. UV additive may be necessary. I dunno, though.

On my 305 LO3, there is an oil pressure sender near the oil filter. It is used by the oil pressure gauge on the dash. Mine went bad and leaks oil. Could this be your problem?

 

Yeah could be as far as the oil leak goes, but how does getting a new cap and doing another pressure test help me with the water? The cap is off when you do that test wether its good or bad? But I'll take the cap to Autozone and see if they can test it. I like the UV idea, will look into that also.

 

Nope.

Also, check around the thermostat housing for any yellow residue (dried coolant). Also check the CTS, coolant fan switch, knock sensor and anything else like that. I have a leak on my T-stat housing that is only noticeable because of the dried coolant. The coolant leaks out so little that it evaporates before it can puddle. You may have the same issue...somewhere.

 

Ive done that as much as I can. For the past couple months Ive been running water instead of coolant because I got tired of putting coolant in it. Plus, I did a radiator flush and had to drain it a couple times. Water became easier. I pulled the block plug and flushed it out, some rust came out then it ran clear. There is some rust in the system, Ive done my best to clean it out. I did not pull the knock sesnor though because my socket wasnt deep enough. After that I never messed with it again. But I havent seen much evidence of frothiness or leakage, even when I was running coolant. There was an orange residue on the pass side and bottom of the motor when I got the car. i figured this was a coolant leak, but since I found a receipt for a water pump in the back, I didnt know if it was a slow leak or water pump failure that caused it. The therm I just replaced this summer, no leak there. But winter is coming, Im going to HAVE to put coolant in it soon, and that makes it 10x messier to deal with all these water issues.

 

I bet it's the water pump.

 

Well, could be. I havent seen any leakage there, but Im going to do the UV test sometime next week or so. I found an Autozone receipt in the back for a water pump dated 8/12 when I was rummaging through the car after I bought it, and the item number was a pump for this car. So if its failed, its been quick. Hopefully the UV will tell me that! That being said, it didnt LOOK new, it was covered in rust. Could very well be they bought a pump, then decided not to put it on, and to sell the car instead. Could also be they stuck a "valuecraft reman" on there. We'll see....

 

I installed a lifetime pump two years ago, and it just failed. Also, check the transmission cooling lines. Good luck.

 

Once I saw a drip of coolant on one of the trans lines where it comes under the front of the trans. I havent seen it recently, but other than a glance now and then I havent been closely checking that area either. UV will tell me I hope....lol

 

But now that you mentioned it, it reminds me. There is a repair in that area by the PO. The metal trans line has about a 3" section cut out and it is spliced together with a piece of rubber hose and four small clamps. I had forgotten that. I dont think its leaking, but Im going to give it a much closer look now.