1275 burning coolant

[Keith_M]

I have a puzzling problem. My '65 Sprite (which has a 1275 instead of a 1098) produces a large cloud of white smoke right when the thermostat opens as the car is warming up. The smoke only lasts a few minutes, and the car runs fine before and after the smoke episode. There is no oil in the coolant, and no coolant in the oil, so I assume that a little coolant is somehow slipping past the head gasket and into one of the cylinders for a short period of time right when the thermostat opens.

My hypothesis for this is that the influx of cool water into the head is causing some local and temporary shrinkage somewhere that is allowing the coolant to get past. Yesterday, I popped the head off to see if I could see a problem, but everything looks pretty good to me (pictures attached). Any ideas on what could be happening?

My current plan is to run the head out to my local machine shop to have them check how flat it is, then reinstall everything with a new head gasket and see what happens.

 

[BlueMax]

I would have the head pressure checked!!

 

[Boink]

I'd follow your present plan (as described). Also, make sure that the brass blanking plugs are all flush (on the head).

 

[nomad]

Reassemble with the black Payen gasket and ditch the copper sandwich. Crack check might be a good idea.

Kurt.

 

[Keith_M]

The head is now at the machine shop. They didn't see anything obvious, but they're going to clean it up, magnaflux it, and resurface it. I'll pop it back on with a Payen gasket and see what happens.

 

[Trevor Jessie]

I've heard of other people with this exact problem. I've never heard of a solution. Ask Peter C. if he remembers who had this issue ... I seem to remember that he was part of the conversation.

 

[Boink]

One occasion, I got amazing puffs of smokes from oil being sucked into the intake manifold passing the PCV valve (that was hooked to the oil separator). I would have sworn it was white enough to be coolant (and it lasted in the air a surprisingly long time)... but it wasn't coolant at all. You can get an AMAZING amount of smoke that way (that looks white) and that soon burns off. I finally took the PCV back out; end of problem.

 

[Keith_M]

One occasion, I got amazing puffs of smokes from oil being sucked into the intake manifold passing the PCV valve (that was hooked to the oil separator). I would have sworn it was white enough to be coolant (and it lasted in the air a surprisingly long time)... but it wasn't coolant at all. You can get an AMAZING amount of smoke that way (that looks white) and that soon burns off. I finally took the PCV back out; end of problem.

Mark,
this is an interesting idea. I will check it out once I get the head back from the machine shop and reinstalled.

I'm not sure why it would only happen when the thermostat opens, though.

Keith

 

[Keith_M]

I've heard of other people with this exact problem. I've never heard of a solution. Ask Peter C. if he remembers who had this issue ... I seem to remember that he was part of the conversation.

Thanks. I was hoping someone might have encountered (and solved) a similar problem. Who is Peter C.? I went to PM him, but there is no Peter C. listed as a BCC member.

 

[Trevor Jessie]

He doesn't post much here, but his user name is PeterC ... he is the owner of worldwideauto. He is known for his shock rebuilds, but is active on several spridget lists and forums.

 

[SaxMan]

Have you actually checked your coolant levels to see how much is disappearing? It almost sounds like a condensation issue, but that would be more typical in an area of low temps and high dew points -- kind of like winter in the mid-Atlantic, and not what you'd expect in Utah.

The only thing even remotely similar that I experienced was a quirk that our '85 Dodge Aries K (and also present in the two other K cars that my family owned at the time...:shame: ), when the thermostat would open on cool, wet days, the sudden influx of heated coolant would cause the condensation that had gathered around the radiator to evaporate, making a nice little white cloud coming from the front of the car. Unnerving, but harmless.

Even when my head gasket on my 1275 blew due to the recessed blanking plug, it never was bad enough to cause white smoke to come out of the motor. The loss of compression was felt on upgrades when the Sprite was not so sprightly, but acting more like "The Little Engine that Could".

Perhaps a compression test or, even better, a leakdown test, would give you a bit more insight as to the cause.

 

[Keith_M]

He doesn't post much here, but his user name is PeterC ... he is the owner of worldwideauto. He is known for his shock rebuilds, but is active on several spridget lists and forums.

Thanks. I feel kinda dumb right now, since I corresponded with him by email when he rebuilt the shocks for the bugeye I'm restoring!

 

[Keith_M]

Have you actually checked your coolant levels to see how much is disappearing? It almost sounds like a condensation issue, but that would be more typical in an area of low temps and high dew points -- kind of like winter in the mid-Atlantic, and not what you'd expect in Utah.

The only thing even remotely similar that I experienced was a quirk that our '85 Dodge Aries K (and also present in the two other K cars that my family owned at the time...:shame: ), when the thermostat would open on cool, wet days, the sudden influx of heated coolant would cause the condensation that had gathered around the radiator to evaporate, making a nice little white cloud coming from the front of the car. Unnerving, but harmless.

Even when my head gasket on my 1275 blew due to the recessed blanking plug, it never was bad enough to cause white smoke to come out of the motor. The loss of compression was felt on upgrades when the Sprite was not so sprightly, but acting more like "The Little Engine that Could".

Perhaps a compression test or, even better, a leakdown test, would give you a bit more insight as to the cause.

I can't see any real decrease in coolant levels, and this is more than a little cloud of steam coming from the engine compartment. This is a LOT of white smoke coming from the exhaust for about 1 min or so. It stops fairly quickly, but for that minute or so, I feel like I'm driving a crop duster, and it's kind of embarrassing.

By the way, I'm originally from Frederick. My parents lived by Holly Hills CC until they died a few years ago, and my sister still lives in Mt Airy. I get back there every so often and I always wish I had one of my LBCs to drive around those winding roads.

Keith

 

[SaxMan]

Hi Keith,

That's a pretty remarkable coincidence. My parents currently live in the retirement community on the opposite site of I-70 from Holly Hills. It was driving to my parents house where I first spied the "For Sale" sign on Longbridgehealey's '69 Sprite IV, which eventually would become Baby Blue. And, yes, the roads in the area are fantastic to drive in an LBC...lots of windy two lane roads that are lightly traveled. There's a pretty active British Car Club in the vicinity, Clustered Spires British Car Club, so there's a pretty good "Brain Trust" of local LBC knowledge, too.

 

[Deleted member 8987]

After all those decades in professional auto repair...and diagnosis...we learned to walk through the cloud, and smell it. Also, to inhale through the mouth once. If it's anti-freeze, you will taste it. Oil you will also readily identify. Overly rich mixture, too.

 

[Deleted member 8987]

Oh...wait...did you change the coil yet? That always solves any problem, or so I've been told.

 

[Keith_M]

After all those decades in professional auto repair...and diagnosis...we learned to walk through the cloud, and smell it. Also, to inhale through the mouth once. If it's anti-freeze, you will taste it. Oil you will also readily identify. Overly rich mixture, too.

I've had the cloud waft back over me while sitting at a stoplight. It's coolant.

Oh...wait...did you change the coil yet? That always solves any problem, or so I've been told.

LOL...coincidentally, I DID change the coil on this car last fall for other reasons, so that's not it. ...or maybe that's what caused it! :laugh:

 

[nomad]

I'm betting head gasket or recession of the brass plug between 2 and 3. If not start looking for crack's in a cylinder!!

Kurt.

 

[Boink]

I'm now leaning to head gasket... but I don't get the fact that it happens when the thermostat OPENS.

 

[Keith_M]

I'm now leaning to head gasket... but I don't get the fact that it happens when the thermostat OPENS.

My hypothesis is that when the thermostat opens, the cool water from the radiator hits the engine and causes the metal somewhere to shrink transiently and open a tiny crack, either in the head itself or around the head gasket. As temperatures even out, the crack closes.

I know it sounds a little far-fetched, but I can't think of any other reason that the appearance of the smoke would be so tightly tied to the opening of the thermostat.

Here's another observation. If I allow the car to warm up slowly, by driving gently or letting it sit at idle, there's no smoke when the thermostat opens. Iif I start the car cold and drive it normally while the temperature comes up, when the temperature gauge hits 160 -- Smoke!