About a month ago my 84 2.5L started blowing white smoke after the car was driven and then shut off then restarted. I could start the engine and no smoke would come out of the exhaust pipe if the car had been sitting for a while. If i drive the car for a bit, say 4 miles or so, shut off the engine for 5 min or so and then restart the engine I will get a lot of white smoke out the tail pipe. The engine also wants to die unless I give it a bit of gas. The start up idle is rough. While I am driving after the exhaust is cleared out I do not see any more white smoke, even at idle. Once everything is cleared out the car runs fine and idles smoothly at 950 rpm.

I have noticed that I am loosing a little anti-freeze. I am loosing about one cup every 2 days or so. It is not leaking anywhere I can see and the car is not marking it's spot when parked. The oil is not milky.

The engine was totally rebuilt 2000 miles ago (just over 1 year). The head was replaced with one that was free of cracks according to the machine shop that rebuilt the engine. Of course there was only a 1 year warrenty on the engine rebuild. I have not raced the engine or over heated the engine according to the temp guage.

How can I pressure check the head and check for a crack?

Where is a good place to get a new head if mine is cracked?

Thank you in advance for any advice.

You can let the car sit overnight, start it for about 10 seconds, remove each spark plug and see if it has antifreeze on it. What concerns me about the machine shop is whether the head was slightly warped to begin with and was not surfaced before they installed it.

The 2.5 heads are notorious for cracking, I've had two do that to me. All it takes is one overheat, sometimes not even that. The last head I bought was $100 for the rebuilt head plus $200 core charge, the extremely high core charge gives an indication how hard it is to find uncracked cores. The core charge may be lower now that that engine's been out of production for so many years and the number of cars with a Duke goes down every day. Easy check is to pull the plugs, the one on the bad cylinder will be perfectly clean and spotless compared to the others.

The machinist should have magnafluxed the head when he rebuilt it.

Is there some reason you don't believe it to be a simple head gasket problem?

and/or a head bolt. 86 & older is famous for breaking head bolts.

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quote Originally posted by KurtAKX: Is there some reason you don't believe it to be a simple head gasket problem?

Personal experience, experience of my machinist, and of the two different large-scale engine rebuilders I've bought from ( http://citymotorsupply.com/ and http://www.blainesmotorsupply.com/ )

It could be a head gasket problem, it could be a cracked block (also common with the Duke, same sources of information), it could be many things. Probability is cracked head, though, by a large margin, IMHO.

Thank you for the replies. I have not had time to start troubleshooting the problem. Right now it looks like I won't be able to start looking into the problem till Sunday June 5th. The machine shop that did the work on the head and engine has a very good reputation here in Indy. He told me he magnafluxed and checked for a warped head before he put the engine back together. I do not know if it is a head gasket or a bolt problem yet. From reading everything I can on the 2.5L engine and with my luck I figured that I have a cracked head.

I will post more as soon as I can. Again thank you for taking the time to reply

Sorry it has taken so long to pull the plugs. It seems like everything else gets in the way. Any way I pulled the plugs and #1 looked wet.

#1 cylinder


#2 cylinder


#3 cylinder


#4 cylinder


Thank you for any advice.

Head gasket is still a contender as the source of your problem. The head comes off pretty quick, and its less than $100 to have it cleaned and checked for cracks.

I have not ruled out head gasket. From the looks of the plugs the head needs to come off no matter what to see what is going on inside the engine.

Those plugs only have 2k miles on them?

Yeah, something's definitely wrong in the motor. Number 4 is the only one that remotely looks kind of normal, except for the coating on the bar, that's bad.

quote Originally posted by KurtAKX: Head gasket is still a contender as the source of your problem. The head comes off pretty quick, and its less than $100 to have it cleaned and checked for cracks.

It was free in my case to find out the head was cracked. I took it to a machine shop for them to re-condition the valve seats. After cleaning it (so it looked like a brand new head), they found a small crack at one of the exhaust valve bowls. So they called me up and gave me the head back.

I think I'm goning to pull the head real soon. I'm also going to check the O2 sensor to see what it looks like. I showed the pictures of the plugs to a gearhead at work and he suggested to check the intake manifold and intake gasket for a leak. He did say there was a slim chance of a leak there. I figure I have to take the intake off before the head comes off so I will look for anti-freeze when I pull the intake.

Finally got time to do a compression check.

With the plugs installed the compression was: #1 - 172psi #2 - 170 psi #3 - 200 psi #4 - 190 psi

With all the plugs removed the compression was: #1 - 177psi #2 - 178 psi #3 - 215 psi #4 - 190 psi

#3 spark plug had the most carbon build up on the electrode.

Pretty high numbers, I would expect to see more in the 125 - 140 PSI range.

I just rechecked the compression check and the numbers are the same. The guage set is new. So, unless the guage is really messed up I think the numbers are accurate.

Dropped off the head this afternoon at the engine shop. Now I wait for the results.

Do all of the pistons come up to the same height when rotating by hand?

Thought I'd update this post.

The head had cracks in it. The engine shop could not find a head in the Indianapoils area that had not been cracked. So they repaired the head and gave me 12 month warrenty on the repairs.

The engine is put back together, but my clutch slave cylinder decided to start leaking and It will not shift into first gear with the engine running. I ran a quart to brake fluid through it trying to bleed the system (using all the advice I found in the forum).

I think I also have a vacuum leak. When I rev up the engine it stumbles and I have to feather the gas pedal to get the rpm up.

So, I'm going to replace the slave cylinder and re-bleed (clutch master is 6 months old). Then check timing just to be sure it is still correct and then go after the vacuum leak.