Auto at rest for 45 minutes - ran well until stopped and turned off. When attempted to restart 45 minutes later, short crank and nothing, tried again and shorter crank. Then only high pitched whirring sound when attempted to start. Oil level higher than full and coolant below top of core.

After considerable efforts - towed back to usual service provider and says it is leak in lower intake manifold gasket. Coolant in front cylinder causing engine to bind up and no start. Says engine in good shape and repair will result in almost as new. This is one owner car, (140,000 km ,84000 miles)very well maintained and only travelling 3000 km (1800miles) per year.
Thoughts? Cause?

If this is hydro-lock the lower intake gasket was not the only culprit in my case. The composite/plastic intake melted from the EGR'* heat and allowed water into my 3800 engine. Inspect the intake manifold above the EGR valve(where mine had melted) to see if it has been compromised. The manifold is a failure item anyway so expect to replace it. The lower intake gasket are failure prone as well. Search the web so that you may understand the problem.

I'd pull all plugs, then hand crank the motor a few times, if there is any liquid in there this should expel it.
Then get the gaskets repaired, but first IMO I'd have a proper compression test done on each cylinder, if you get that done please post your numbers here.

grandpa is right the EGR gasses can cause an issue, if you get it repaired have them use the Fel-PRO Aluminum gasket kit, and get a Dorman Upper Intake Manifold and Kit, may as well replace the upper intake, the newer Dorman ones are redesigned and have beefier baffles, and the gasket kit will come with a reduced diameter EGR Stove Pipe, this will fix the EGR issue.
Also make sure they use the Dorman Aluminum Coolant Elbows, and not the old plastic ones!

Failure of the lower intake manifold gasket, and failure of the intake manifold above the EGR are probably two of the most common failures on the 3800. Sounds like you are on the right track. Make sure you change the oil after the work is done, and before you start the engine.

Thanks to all for messages. Auto being repaired now and all fields appear to be covered.
Oil will be changed then rechanged after the engine is started.

I do not understand what you mean by replace manifold.
Oil pan gasket assembly, thermostat and gasket, starter motor that burned out, Valve cover gasket, PCV valve kit, all spark plugs to be replaced as one necessary and to be sure others not contaminated, lower intake manifold gasket assembly all to be replaced, plus removal of oil pan to clean out antifreeze in bottom of pan and new antifreeze.

As stated in my earlier post, there are two failures that are common on the 3800 that can cause coolant loss. One, which you seem to have experienced, is failure of the LIM gasket. The other is failure of the upper intake manifold due to contact with the EGR stove pipe. The heat from the stovepipe degrades the plastic to the point coolant that flows through this area can flow into the intake manifold and cause hydrolock.


I suggest you have the upper intake manifold inspected in the area of the EGR stovepipe for signs of plastic degradation. If you are changing the LIM gasket, now is the time to make sure you don't have a problem in this area. You may have to replace the upper manifold.

That is why I suggested just replacing the whole upper intake, of course you can inspect it, and it it is fine just get the gasket kit, and be sure the EGR Stove Pipe is removed from the lower intake manifold, and the kit had a reduced diameter one that goes in place of the old one, if you do not do this then consider blocking the coolant ports off at the lower intake manifold.
If the mechanic is good, and familiar with this 3800 issue, then he should know to replace the EGR Stove Pipe....

William
When car repaired should compression testing be done on all cylinders?

Not necessary, but wouldn't hurt. Depends on what your mechanic wants to charge to do it.