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Coolant Loss- no dripping and white/bluish smoke!


adrianolsen
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We got a 1974 2002 a couple of months ago we are gradually losing (faster than normal) coolant. there are no coolant drip marks anywhere to be found and im guessing that the coolant is somehow (im a total noob but really interested in learning!) leaking into the engine and showing up when slowing down from high speeds as whitish blue smoke out of the tailpipe. The stock radiator is pretty beat up (bent fins) and I was curious if replacing with a refurbed stock radiator (maybe upgrading to 3 cores + adding a better 5 blade fan?) would be the right move to address the problem and improve engine cooling. Thanks in advance for the time and thoughts!

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You are right. White/blue smoke is coolant being burned in the engine. That is a heaping pile of not good. Most likely a blown head gasket. Your beat-up radiator probably does not keep the car cool. I bet it overheated at some point in the past and blew the head gasket and possibly warped the head.

Since water does not combust or lubricate very well you should get it fixed as soon as possible but it will not be cheap.

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next time you drive the car till HOT,

park it,

do not touch the rad cap - leave it alone to hold

HOT pressure

remove all the spark plugs,

let it sit for 1 hour 45 minutes

now crank the motor (have a helper man the key)

and you watch what pumps out of the

spark plug holes. Dares yer answer.

p.s. - was there crusty deposits on the spark plugs ?

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read-up, buy a torque wrench and a head gasket. Maybe your head is OK, pull it off and bring it to a shop so they can check it out, and plain it if needed.

Lots of threads on here about replacing a head gasket.

Good luck-

Scott

uhhhh, am I the only one that's thinking blue smoke on deceleration is the trademark of bad valve seals (and oil, not coolant which is white smoke)? You can fix them while the head is off for the headgasket (otherwise normally its not worth fixing)... but are we certain the headgasket is leading to the coolant loss? It could be seeping out somewhere else, and might need some more diagnostics before pulling the head off.

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uhhhh, am I the only one that's thinking blue smoke on deceleration is the trademark of bad valve seals (and oil, not coolant which is white smoke)? You can fix them while the head is off for the headgasket (otherwise normally its not worth fixing)... but are we certain the headgasket is leading to the coolant loss? It could be seeping out somewhere else, and might need some more diagnostics before pulling the head off.

I took him for his word that it was not leaking water. Sure it could be burning oil but my bet is on the head gasket.

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read-up, buy a torque wrench and a head gasket. Maybe your head is OK, pull it off and bring it to a shop so they can check it out, and plain it if needed.

Lots of threads on here about replacing a head gasket.

Good luck-

Scott

uhhhh, am I the only one that's thinking blue smoke on deceleration is the trademark of bad valve seals (and oil, not coolant which is white smoke)? You can fix them while the head is off for the headgasket (otherwise normally its not worth fixing)... but are we certain the headgasket is leading to the coolant loss? It could be seeping out somewhere else, and might need some more diagnostics before pulling the head off.

I think the bulk of 02's on the road send out whitish blue smoke on decel after steady driving. That is usually bad seals/guides etc in the valve area. Most head gaskets i have seen leak cause smoke, white smoke, all the time, not just at decel.

Follow CD's advise before you yank the head off. You might just have a crapped out radiator cap and its just steaming out while you drive

I am no expert

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uhhhh, am I the only one that's thinking blue smoke on deceleration is the trademark of bad valve seals (and oil, not coolant which is white smoke)? You can fix them while the head is off for the headgasket (otherwise normally its not worth fixing)... but are we certain the headgasket is leading to the coolant loss? It could be seeping out somewhere else, and might need some more diagnostics before pulling the head off.

I'm with KFunk.

You did not specify how much coolant you are losing. Any loss is faster than normal. Coolant system are not supposed to lose any coolant.

You also did not mention if your engine overheating. Is it overheating just when you end up low in coolant?

Coolant will evaporate and not show evidence of drips. It may be as simple as a bad cap and your coolant is leaking when the system is pressurized. Yu may also have a small leak at the back of the head, at the outlet pipe and the coolant is dripping on the hot exhaust and evaporating.

The whitish blue smoke on decel is usually evidence of failing valve guides and seals. Coolant being digested in the combustion process will show steam out the tailpipe at all times especially when cold. And it would have a distinctive sweet coolant smell.

Your radiator looks like it needs attention. I would start there and see if your temp improves and if your coolant leaks persists. You will need to tend to the radiator anyway so there is no loss there.

You can conduct a pressure test. Most shops have a gauge that connects to the radiator. The system is pressurized and tested for leaks. A cracked head or blown head gasket will cause the gauge to flutter when the engine is running.

I would test these before taking the head off. A head job is involved and not cheap. I would also not recommend taking the head off and not doing a valve job, replacing the guides and seals, pressure testing and resurfacing. It's not cheap but you're already half-way in it.

Best of luck.

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thanks for all of the useful info, i'm going proceed in the morning - addressing the valves and seals before checking the head. really taking good look at the source of the leak before i draw any conclusions and pay the big bucks. here are more facts about the issue that i have remembered. maybe they will help to narrow to a solution...

more facts:

1. since i've owned it (october -with some days around 80 and driving it for 2 hour periods) the engine has never overheated. the gage, which seems to work well has never been more than a little over half and I've never seen steam coming from the radiator.

2. the smoke that I'm talking about (more white than blue) only occurs when I'm driving at high speeds - say 55mpr and above - and it only happens when i've let off the gas to break or slow down and then put my foot back on the gas to accelerate - as soon as i put my foot back on the gas, that's when the smoke comes out of the exhaust (a considerable amount - an embarrassing amount)

3. it's hard to tell how fast the coolant is leaking, and i haven't kept best watch on it. but i'm pretty sure that while it's sitting it doesn't leak.

it's only when i drive it. and i if memory serves, the level is lower after longer/faster drives on the highway when the car is hot.

again i haven't seen any coolant on the ground, but the car has been outside on gravel, i will put cardboard down tonight. i have noticed a bit of blue residue around the radiator cap that has dripped down the radiator as well.

my oil levels have stayed relatively steady. though I have added about a quart since october when the oil was changed.

thank you again! i'll update tomorrow!

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Have you pulled your oil cap? How does it look? What color is the oil? Clear and fresh is normal...black means change it...chocolate brown means you have oil and coolant mixing....thats your answer and it means, head gasket, or warped head, or cracked block. Head gasket is USUALLY what it is. A bad radiator will leak but you should see evidence...like green coolant droplets in the engine bay. Smoke on deceleration can be valve guides...OR piston rings. Smoke on acceleration and ALOT of it sounds more like a head gasket to me. When my head gasket started to go I got smoke only when it was cold...Once the car warmed up it ran fine and never gave me a problem...When I swapped it out...I never lost any coolant. Before I swapped it I was adding a considerable amount weekly.

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1. A (semi) surefire test for water (coolant) in the exhaust: with the engine fully warmed up and running (tailpipe hot to the touch), place a piece of kleenex over the tailpipe and hold it in place for 10-15 sec. If there's excessive moisture in the exhaust, it'll disintegrate the kleenex and it'll be wet to the touch.

2. I had a similar slow but steady coolant loss (about a quart in 6-800 miles) with no leaks on the ground or anywhere in the engine room. Even the compression seemed normal. Finally on the upteenth compression test, one spark plug came out wet with coolant. Pulled the head and discovered the water passage in the head (#1 cyl) directly over the exhaust port had eroded until it met the combustion chamber, thus allowing coolant into #1 cylinder in small but steady quantities. Two of the other three cylinders' water passages were about to do the same thing. Had the head welded up, planed and stuck it back on. that was 65k miles ago and all has been well since then.

3. One more thing to check: get under the car and look up at the underside of the water pump--there's a weep hole at 6 o'clock. If you see a whitish deposit dribbling from the hole, the water pump is about to die. It will leak through the weep hole, and air from the fan and heat from the engine will evaporate the coolant before it can drip on the ground.

Let us know whatcha find...

mike

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Hah, just my luck.... guess what happened to me this morning. After a slow coolant loss all this past year, and weird occasional rising temperatures that couldn't be fixed by replacing all the hoses/t-stat, etc....

It started putting out a whole lot of white smoke when cold, and it sure smelled sweet, and there's a slight milkiness around the top of the dipstick and under the oilcap. Welp, guess it's that time of year anyways. Might as well park it and put the Miata into action, and swap the wheels/tires onto it. I'm wondering about just droppin the pan as well this time, and throwing in some new rings that are long overdue. Maybe a better head and cam could be in order, as well. I guess I got all winter to take my time with it.

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