1940 lasalle runs hot

[Chip Parman]

Greetings all,

I am the owner of an auto repair shop in JAX FL. area, and have a customer who owns a 1940 Lasalle.  This car is a convertible, and shows 24,000 miles on it.  The car sat for many years before the current owner restored it.  The engine was rebuilt by a local shop that I do business, and the car was assembled by someone I trust.  Here is the problem

the car runs about 3/4 the way up the temp gauge at cruise. After the engine gets up to this temp, and the car sits at a light it will continure to get hotter.  I used an infrared thermometer to see how hot the engine is , and it is about 210-220 degrees at just over 3/4 on the gauge. Looking into the radiator it seems clear.  as long as you are moving it will run
about 3/4 up the gauge.  we have zip tied the thermostat? door open so we know it will not close the vents in front of the radiator.  Should this car have a fan shroud.

When the car was restored the shop that did the assembly told me that hthe engine seemed very tight while trying to fire the engine for the first time.  the car probably has less than 500 miles on it since this work was done.  When we frist saw this car it would not turn over at all.  It had been sitting for 4-5 years. We freed up the engine, and put an 8 volt battery in it.  seems to crank well.  thanks for any help in advance

Chip Parman
Mayport Car Care Center
904-246-4805

[baxter culver #17189]

I have a 39 Cadillac 60S.  It is essentially the same car.  Have you used your infrared temp sensor to survey the whole radiator?  look for temp differentials upper-lower, left right, etc.  If the water pump is working normally, and the shutters are open, the radiator would be suspect--it is 65 years old.  I had to replace mine to solve my heating problem.  Also, check the temps at various places on the heads.  Sediment can build up esp in the rear areas and prevent proper coolant circulation.  There is a Cad service bulletin from the period detailing how to clean the water jackets by removing head bolts and using airpressure to purge the system.  You might be getting a hot read from the temp sensor because of blockage in the area around the sensor.  (If the engine was boiled out as part of the rebuild this shouldnt be a problem)

[chip Parman]

Thank you,

I did as you suggested, in checking various places on the engine with the engine running and not.  seems to be consistent thruout the engine.  I did this about a month ago, and am going to do this again today.  I have a customer /friend who is a VERY YOUNG 92 years old that was a machinist by trade and Bruce used to rebuild these engines after the war.  Bruce tells me that these engines had a problem with the drives side of the engine building up debris in them because of the one water pump.  I am assuming that the engine is clean, because of the low mileage on the engine, and because I used the same rebuilder that rebuilt this engine ( I know their work)  I think I am going to retest the temps, and might remove the temp sender to see if there is any debris in that hole.  If there is i thought about removing the heater hose that is attached to the left ( drivers ) cylinder head and the hose that attaches near the water pump and hook up a water hose and flush the engine that way just to see what comes out. Thank you again for your imput

Chip Parman

[Bill Ingler CLC# 7799]

Let me add a few thoughts to the excellent response by Baxter. I had much the same problem with both my 41 and 47 until I put in new cores. Both my radiators appeared good but once the top tank came off, one was about 50percent pluged and the other 40percent.When ever one of these flat heads is rebuilt, one of the most important areas that shops sometime overlook is properly de-rusting the block and heads. Flushing the block and heads with high pressure hot water won`t hack it. The only way to properly clean block and heads is take them to a metal cleaner who tanks them and then reverses current polarity in the tank every few hours. This knocks out the rust, the water passages in the block and heads comes out looking like new. If your customer`s car engine block and heads were properly cleaned, the radiator core replaced, then the car temp gage should show about mid point and the top of the tank should show a temp about 175-- at normal cruise. Any flat head Cadillac/LaSalle will rise a little at a stop light. Here again though if the rise in temp is large then that also tells me the radiator has some restriction. There should also be a large spring inside the lower radiator hose to water pump to prevent cavation by the water pump thus partialy closing the hose. I believe that the 40 LaSalle also carried a A/C radiator cap model RC-3 which was rated at 7 lbs.

[Chip Parman]

Thank you for the response.  The local company that rebuilt this engiine about 6 years ago is the same company I have used for 15 years.  I trust them, and am not sure if they have the ability to reverse current polarity.  My company is a 33yr old general auto repair shop, that has and is growing a following of collector cars.  We are a bunch of 40-50 yr old guys that appreciate how much work and pride goes into restoring and maintaining a part of American history.

Thank you again

Chip Parman
Mayport Car Care Center
904-246-4805

[Michael Stamps 19507]

Hi Chip,
  I doubt you remember me but I was the guy that came by about a year ago with the gold 70 Deville.  I just wanted to say that you are the highlight of my drives up Mayport road when I get to see all of those great old cars.  You are in good hands here and I still may get you to do some work on my 70.

Stampie

[chip Parman]

Michael,

I am sorry but I do not remember you.  I am almost 50, and to quote Toby Keith " I aint as good as I once was" .  Thanks for the kind words.  Yes we are fortunate to have some great customers that will let us work on their cars.  It is the fun part of owning my shop.  Please stop by and say hello.  I have a 67 rust bucket convertible at the shop now.  Looking for a gas tank and a sender.  The car is not worth fixing, but the owner  has had this old girl for 30 years.

Thanks!
Chip

[Michael Stamps 19507]

Im working in Ponte Vedra tomorrow (Comcast) but Im off Thursday so I might swing by.  Id love to look at the 67 and the LaSalle.

Stampie

[JIM CLC # 15000]

06-14-05
CHIP, ask the rebuilder if he remembers if he/they made the hole larger in the Right Side Head, the hole under the top radiator hose manifold. The hole in the Left Side Head is about two-times larger then in the RSH so the flow of coolent from both sides of the engine is more or less equal. That is one mistake that most people who are not knowledge of the engine will do whenever they overhaul an old Cad/Las engine. But on the other hand you have indicated that the temp. is about the same all over the engine. I will have to go alone with the other posts and say look for a plugged/bad Radiator.
Good Luck, keep up the good work, Jim

[baxter culver #17189]

One additional thought.  When I bought my 39, the temp sending unit stopped working.  I replaced it.  A couple of months later, the car started "running hot".  As in almost to the top of the guage.  My crude pyrometer said the head temp was ok.  I removed the sending unit and placed it in a pan of water--room temp.  then slowly raised the temp charting the resistance and temp on a scale.  Sure enough, the "new" temp sending unit was toast.  Replaced it (Terrell Machine) and everything got happy.  So, dont trust the guage too much!

[Michael Stamps 19507]

I just went by Chips shop to look at the two cars.  First that LaSalle is amazing.  Thats first 40 that Ive seen in person and you can tell that a lot of attention has been given to her.  Amazing quality on the black paint job.  If Chip thinks that 67 is a rust bucket Im sure glad he never saw my old 67.  Another good car that Im sure the owner loves.

Stampie

[Chip Parman]

Thanks for the response,

I spoke to the rebuilder, and he like me cant remember 6-7 years ago.  I had the radiator rodded out, and the radiator shop found nothing wrong with the radiator.  very clean inside, and radiator shop thought the radiator had been recored before.  I recieved an email from Don Boshara, concerning the heater hose routing, and completely bypassed the heater all together.  Today in sunny Florida it is about 96 drgrees.  still runs too hot??

after letting this old girl run for about 25 minutes at my shop, I drove it about 5 miles and watched the temp gauge continue to climb past 3/4 on the gauge.  When I got back to the shop I left the car running long enough to get my infared and shoot the motor.  The temps on BOTH heads were about 207 at the bottom of each head, and 215 at the tops.  both very consistent.  we also checked the timing and mad sure it was not retarded, gave it a little more advance??  hot and tired.  will drive in the a.m.

Thanks
Chip Parman
Mayport Car Care Center
904-246-4805

[chip parman]

I guess your noise was taking a break.  Big time fuel leak at the gas tank.  floor boards are almost not there.  Nice to see you today!
    Chip

[Michael Stamps 19507]

I guess Im so used to my friends garage where were swapping a 472  into a Datsun 260Z that it just smelled like a garage to me.  Thanks for letting me look at the two cars.

Stampie