Jump to content

Strong coolant smell when starting


iowa51

Recommended Posts

'51 Plymouth with stock 218. Engine was rebuilt less than 1,000 miles ago.

 

After the car has sat for a longtime (months) when starting it up I will get a strong smell of antifreeze/coolant and white smoke comes out of the exhaust for a few minutes. It has probably happened since the engine was rebuilt but never realized because I would always pull the car out right away and the weather was a always little chilly in the spring so assumed it was just vapor due to the cold air and moisture that may have been it the exhaust system,  didn't really smell the coolant as by then it was idling outside. 

 

Earlier this week started it up after sitting for about 2 months and let it idle in the building before pulling it out and notice the smell/smoke. Lasted less than 5 minutes. 

 

Brought it home and checked things out a few nights later. Coolant level is okay, an inch or so above the fins. Filled it full to the top and let the car idle for 15-20  minutes and about 3/4 of the way to hot on the temp. gauge, no bubbles coming up through the radiator.

 

Something to be overly concerned about? As posted previously this rebuilt engine runs MUCH warmer than my old engine, especially in parades, if this is related to the problem.

 

 

Edited by iowa51
Link to comment
Share on other sites

Did you re-torque the head bolts after a few warm up cycles? My Coronet runs hotter since the rebuild also, 190 average. I’ve never let mine sit more than a few days so I’ve never had any problems. Have you checked for coolant in the oil? There is a lot of knowledge on this forum. Someone will point you in the right direction. Good luck.

Link to comment
Share on other sites

No coolant in the oil as far as I know. Oil is clean and just below the full line. Did an oil change at 100 miles after the rebuild on nothing out of the normal.

 

Re-torquing the head bolts is something to consider as I don't think it was probably done. Easy to do as the head bolts were numbered in the order they were torqued. Do I do this to a cold, warm, or hot engine? Pound/feet to torque it to? The shop manual is back at the building where I store it.

Link to comment
Share on other sites

Is it possible that when you were working on the engine, some coolant spilled into the exhaust pipe? The reason I ask this is because we were doing a valve job on an engine and during the head removal, coolant found its way into the exhaust system. After reassembly, the engine exhaust reeked of anti-freeze and put out white steamy smoke for almost an hour before subsiding. Where you say that your oil looks clean and no apparent loss of coolant is evident, it could be a possibility. I hope that that is all it is. Good luck to you.

John R

  • Like 1
Link to comment
Share on other sites

31 minutes ago, John Reddie said:

Is it possible that when you were working on the engine, some coolant spilled into the exhaust pipe? 

John R

That is a possibility but in the hundreds of miles I have driven it since any major engine work I would think this would have burned out.

 

21 minutes ago, Plymouthy Adams said:

did you seal the manifolds studs on install?   yes the gasket should help seal this also but with exhaust you get a venturi effect....

Yes, the studs were sealed, learned that from personal experience many years ago. It only smokes/smells when it has been sitting for an extended period of time. Went and started it today after sitting for 2 days and no smoke/smell. 

 

Will try re-torquing the head bolts and see if that helps. 

 

 

Link to comment
Share on other sites

Have you carefully looked at the oil?

Have you changed the break in oil since the rebuild? 

Letting the engine set for a couple days then loosening the drain plug almost till it's off would let green coolant come out first before the oil. If this happens to be the case  most likely a head gasket leak on a flathead. This also would push some coolant into the exhaust sytem and also cause a initial single cylinder engine miss upon start up

If the leak is into the exhaust manifold causing the white smoke and smell of course that's a stud or crack in an exhaust port or lower seat area seat possibly.

This  is assuming there was never a big loss of coolant into the exhaust system from the tear down...kinda unlikely after nearly 1000 miles of driving since the rebuild.

Just some more hopefully helpful ideas.

  • Like 3
Link to comment
Share on other sites

From your description, lack of bubbles in radiator etc, it doesn't really sound like a head gasket.  but, if you want to be sure, there are combustion gas test kits/tools for the coolant.  $40+ at most parts stores. Or, some may have them for loan.

Link to comment
Share on other sites

8 hours ago, Jerry Roberts said:

Don't fill it to the top . When the engine gets warm , it will overflow . 

Only did this as a test to see if bubbles were coming up through the radiator, wanted the coolant to cover/fill the upper radiator hose.

 

After it cooled down put the cap back on and a catch pan underneath. Restarted and let it idle for awhile and have the coolant overflow into the catch pan as it heated up.

Link to comment
Share on other sites

Wispy white smoke for a bit is nothing to worry about.  But, white smoke with that coolant smell is.  The short of it is that there is coolant burning off in one or more of the combustion chambers.  Leaking head gasket, cracked head, or cracked engine block, none of which are minor issues, are the usual causes.  Bubbles in the radiator/coolant when running is an indication that the gasket is the culprit, but just because there are no bubbles doesn't rule the gasket out.  Nor does having a recently rebuilt motor rule out a cracked head or block.  Though it may take a while, it will only get worse if not addressed.  That being said, several years ago our D24 had an issue with the thermostat housing gasket leaking, which would cause coolant to pool up in the #1 spark plug well.  If left to sit for long enough, some would seep into the #1 cylinder, and we'd get that coolant smell and a little white smoke until it burned out.  Trued up the housing base, replaced the gasket, and it hasn't happened since.   

  • Like 1
Link to comment
Share on other sites

3 hours ago, Dan Hiebert said:

Wispy white smoke for a bit is nothing to worry about.  But, white smoke with that coolant smell is.  The short of it is that there is coolant burning off in one or more of the combustion chambers.  Leaking head gasket, cracked head, or cracked engine block, none of which are minor issues, are the usual causes.  Bubbles in the radiator/coolant when running is an indication that the gasket is the culprit, but just because there are no bubbles doesn't rule the gasket out.  Nor does having a recently rebuilt motor rule out a cracked head or block.  Though it may take a while, it will only get worse if not addressed.  That being said, several years ago our D24 had an issue with the thermostat housing gasket leaking, which would cause coolant to pool up in the #1 spark plug well.  If left to sit for long enough, some would seep into the #1 cylinder, and we'd get that coolant smell and a little white smoke until it burned out.  Trued up the housing base, replaced the gasket, and it hasn't happened since.   

Good point.  Years ago I had one in the shop that was doing something similar due to an unsealed head bolt seeping.

Link to comment
Share on other sites

Run it a while till warm. Take the plugs out and smell them. Do they smell like coolant? If so you have a slow head Gasket Leak.

Particularly if say 1 and 2 smell like coolant as was the case in my Head Gasket Leak, or say two adjacent Cylinders.

Tom

Link to comment
Share on other sites

Re-torqued the head bolts.

I was able to tighten all of them some, the middle ones a little more. 

 

As I said it only did this after sitting for a few months, might need to wait until next spring to find out if this fixed it. If not, looks like I will need to pull the head and investigate further.

Link to comment
Share on other sites

Make sure no coolant (antifreeze) is in the oil...it will damage the rod, cam and main bearings.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use