Pre-war (up to 1942) 1939 Lasalle Emergency Flathead Overheating

[39LaSalleDriver]

I know this has been beat to death in some ways, but I've got a strange situation going on.

Drove 700 miles in my LaSalle to a show and was planning on driving the 700 back to home and then the next morning going up to the GN. About halfway here my water pump started leaking, but I made it to Reading, PA (my destination). Fortunately, my s/o thought it prudent to bring the modern car as a backup. Unwisely, I did not have a spare water pump with me, so I called Kanter to see if they had a water pump in stock so I could drive the extra two hours up there to pick it up.

Did that. After digging around a bit, found a shop that could change my pulley over and I spent half of yesterday changing out the water pump in the motel parking lot. What a PITA....

Here's my problem. Now my dash gauge shoots up to about the 3/4 mark in about 2 minutes after starting, and pegs "HOT" shortly thereafter. It has NEVER done this before. I'm NOT leaking water at pump or hoses or anywhere else. And it's not boiling over at the cap, everything is tight.

So I shut it down, and restart about 30 seconds later. Turns over great (a good sign the engine is not actually hot) and the gauge goes to the halfway mark and it starts pegging all over again within a minute or two.

I have polarized the generator to make sure nothing's going on there; started engine this morning from dead cold with the radiator cap off to let it idle and see if there's an air pocket in the block. While doing that, it starts the same thing (pegging out), only this time I'm taking readings with my digital thermometer that I wisely threw in the trunk. While it is pegging out, I'm getting around a 150 degree reading on each of the cylinders, maybe 160 on my outlet hoses. Nothing that I would feel is dangerous especially since I'm sitting at idle. From what I can tell the pump is working fine so that doesn't appear to be the issue.

I'm convinced that something isn't right, but I'm more than a bit scared to drive 700 miles home with no "real" reading on my dash gauge, and hoping for the best. BTW, it ran about about the 3/4 mark all the way up here so I was real pleased with that.

Does anyone have any suggestions because I'm in a real bind here...

Thanks

[KenZ]

Maybe install an after market temperature gauge just to get home.  They are cheap, easily installed and can be found at most auto part stores.  Good Luck! 

[Bobby B]

Maybe install an after market temperature gauge just to get home.  They are cheap, easily installed and can be found at most auto part stores.  Good Luck!

I would suggest the same....I disconnected the factory gauge in the '47 for that same reason. It isn't really a good indication of what's going on or what's about to happen. Your readings are on the low side for a flathead, so I wouldn't worry. Your main concern is probably trying to get it back home safely. You probably already know all the problems ( and solutions) we have with our Flatheads running on the Hot side. Air pockets, collapsing lower hose at higher RPM, impeller slipping on water pump shaft /incorrect impeller depth, crud in the block, cracked heads/ block, etc., etc. Good Luck!
                                                                                                                                                                   Bobby

[Daryl Chesterman]

Jon, I know nothing about the LaSalle engine, but is it possible that where the temperature sensing bulb goes into the engine there is an air pocket?  If you loosen the fitting for the sensing bulb end you could see if air or coolant comes out and that might help to see what the problem is.

Daryl Chesterman

[39LaSalleDriver]

Well, I'm pleased to report that I might have been too hasty in pressing the panic button, it has been a very stressful trip so far. But thank you to those who commented or made recommendations. After running my tests this morning I let it sit for about two hours and fired it up. Drove it quite a bit today with plenty of slow speeds and sitting in modest traffic and it held up great. Dash gauge hovered right around the halfway mark, and I shot a reading with my digital thermometer on my cylinders, outlets, and lower hose and found everything reading at around 180 degrees. I'm considerably more relieved at this point. In a weird way, it seems to be running cooler than it ever has before.

Still don't know what the gremlin was, but I suspect my first instinct was correct that there was an air pocket in the block causing the issue. Anyway, wish me luck and perhaps I can still make it up to the GN this coming week.

[z3skybolt]

Congratulations.  You either found the problem or it fixed itself. I am really impressed that you have taken the LaSalle on a 700 mile trip. Way to go. Farthest I have been is 135 miles....but planning longer trips in the future.

You are an inspiration,

Bob R.

[39LaSalleDriver]

Congratulations.  You either found the problem or it fixed itself. I am really impressed that you have taken the LaSalle on a 700 mile trip. Way to go. Farthest I have been is 135 miles....but planning longer trips in the future.

You are an inspiration,

Bob R.

Or a fool... Jury is still out on that. Honestly, other than this water pump business (which I'm sure was my own stupid fault to begin with), the 39 has performed beautifully and certainly garnered a lot of favorable attention.

No, my issues seem to have worked themselves out so far as I can tell. It's going to be a long ride home because it appears I'm going to have to dodge some rain as well. Not wild about car getting wet, but I pretty much refuse to drive on wet highways with bias tires.

I figure by the time it is all said and done, I'll have driven around 2,000 miles in just over a weeks time. Not bad for an 80 year old car.

[harry s]

Jon, Better to press the "panic button" too soon rather than too late. The infra red thermometers are great. Hope to see you in Louisville.    Harry

[carlhungness]

       Of course I'm glad to hear the problem isn't one after all. But I'm a little disappointed to hear someone is really impressed when a 700 mile trip is undertaken. I thought nothing to driving my '37 LaSalle from Denver to Los Angeles, and actually carried on for another 70,000 miles before the engine quit. I put in another and logged 40,000 more miles before I tore it apart.
       Yet I have to admit I'm installing a 1974 500" Cadillac in my rebuild of the car. They were built to drive and I plan to do so.

[39LaSalleDriver]

Jon, Better to press the "panic button" too soon rather than too late. The infra red thermometers are great. Hope to see you in Louisville.    Harry

I suppose you're right in some ways. I just hate asking for help when I SHOULD know the answers already. It was just a stressful situation that was looking pretty grim there for a while.

Of course, now I've had to face an entirely different problem. Left Pennsylvania this morning and my objective was to stay in Bristol, TN tonight. Made it through some light rain with no problems and about two and a half hours north of Bristol picked up someone who started bird dogging us. At first it started off innocent enough, he passed me, waved and honked as he passed me and I responded in kind. Then he dropped back behind me and the chase car my missus was following in and started following our every move. Slowing down, changing lanes, etc., etc., etc. Keep in mind we were doing between 60 and 65 mph on clear roads in a 70 zone so there was no other explanation. It honestly started to weird us out that someone would follow us in such a fashion for two and a half hours. Maybe it was innocent enough, he just wanted to talk cars for something...maybe even someone from the CLC, I don't know. It's one thing to get hit up by someone at the gas station, restaurant, or grocery store...okay, I get it, people are sometimes curious. But it's a whole different animal to more or less stalk and shadow your every move on the highway for over two hours. Very uncool. Quite frankly, that's a good way to get shot.


Anyway, we were about five miles from our destination and I called up the missus on our walkie talkies and told her I was going to speed up and try to put some distance between us. He ends up following suit, but I pop back in between some cars where he can't squeeze in and shoot off the next exit at the last second where he can't follow. Unfortunately the missus had to stay on track so I told her to take the next exit and wait while I catch up. Well, since I had been pushing pretty hard driving up and down mountains for about nine hours plus trying to dodge this joker, the heat started catching up with me so I shut it down to let it cool off for a few minutes (just natural, not another water pump problem). Called the missus to tell her what was up and found out she had shaken our "friend" off her track, but worse still, the LaSalle now had a dead battery.  Tried to jump start it, but "no go". It would grind and turn, but it was too hot to crank over effectively. 

Fortunately, there was a Tractor Supply down the road about a mile that was closing in about 10 minutes so I was able to get up there and buy a new battery to drop in. Whew...back up and running. Got to hotel and parked it, went to disconnect the battery (thumb wheel type disconnect) and found it was stuck solid even though I had used it at our previous hotel the night before.

Now I'm beginning to wonder if that was the culprit for the battery "failure" to begin with. Did it get hot and have a meltdown while pushing it so long and hard down the road? Did it get fused when I was jump starting it? Tired of fooling with it tonight, will put the voltmeter to it in the morning and see what's going on. I'd hate to lose an Optima battery that's held up pretty good for me the last year and a half...

       Of course I'm glad to hear the problem isn't one after all. But I'm a little disappointed to hear someone is really impressed when a 700 mile trip is undertaken. I thought nothing to driving my '37 LaSalle from Denver to Los Angeles, and actually carried on for another 70,000 miles before the engine quit. I put in another and logged 40,000 more miles before I tore it apart.
       Yet I have to admit I'm installing a 1974 500" Cadillac in my rebuild of the car. They were built to drive and I plan to do so.

I wouldn't say I'm "disappointed" in anyone for not driving long distances in our cars. I get it, but then I'm no stranger to walking where angels fear to tread at times, and perhaps I should be more cautious. I'm sure there are plenty of folks who would consider me reckless, foolhardy, stupid or what have you for taking an 80 year old car on such a trip. But hey, one man's recklessness is another man's boldness. I read on this forum one time words to the effect of 'you'll never find what you and your car are capable of sitting in the driveway', and I agree.

I'm with you, as far as I am concerned my car is meant for driving whether it be around town or halfway across country. As long as I can afford it, hold it together, whatever, I'm going to drive mine. It's not a "show car" it's a "driver." A respectable looking driver which I'll continue to improve upon, but a driver nonetheless.

Stand by for more adventures! 

[z3skybolt]

Carl said that he ....."was disappointed that someone (me) was impressed" ..... that someone would take an 80 year old LaSalle on a 700 mile trip: ultimately a 2,000 mile trip.  I intended it as a compliment to you USNTar and I am sorry that Carl was disappointed by my compliment.

I drove my LaSalle over 3,000 miles last year: 6,000 miles in the last three years and the engine was out for overhaul 9 months of those three years. Although beautifully restored.... she is no trailer queen. I just have not taken her on a trip more than 134 miles from home...but would not hesitate to do so.

Your trip will total nearly 2,000 miles. Probably less than 1% of the CLC members have ever taken an 80 year old car on a trip that long.  I REMAIN IMPRESSED.   And wish you every good fortune in your adventure.


Keep us in the loop,

Bob R.

[39LaSalleDriver]

Thanks Bob, I certainly took it that way. 

Seems like disaster begets disaster though.    My latest report is not a good one I'm afraid. Started out this morning and everything was fine. Tooled around downtown Bristol a bit trying to wait out the rain before hitting the interstate. Made it 80 miles and it started pegging to HOT again. 

Pulled over, let it cool off a bit, added some water, and couldn't get it to start. Was turning over, but seemed like no fuel. Odd, because I run an Airtex in series with the mechanical fuel pump. Turns out my Airtex isn't working now  Don't know if it fried when trying to jump start or what (I have a fuse block I run it through). Shot some starter fluid down the carb and got it running again. Got back on the interstate and within 3-5 miles it started pegging to HOT again...

So I finally decided to make the call I didn't want to make to AAA. Thank God I have their highest tier package. I was just about five miles over the 200 mile limit from home. The shame of being towed home is going to sting for a while.

My LaSalle won't be coming to the GN, but I will probably drive up in my regular car anyway. Now I get to figure out what all went wrong and how to fix it. Fuel pump is a cheap and easy fix. I'm more concerned where the water in the cooling system is going to. Is it p*****g out the overflow while going down the road (only dropping a cup or so when I stop), or is it going where it shouldn't in the engine a la blown head gasket? Thus far, no white smoke out exhaust, bubbles in the radiator, or residue on my dipstick. Or is it possible my new water pump from Kanter failed? I'm just going to have to sit down and start doing some testing to figure it all out.

[Bobby B]

Jon,
Hi. Please keep us in the loop.....I went through your same exact scenario and it wound up being a cracked block. Car would go 70 MPH all day until I got off the road. One day fine, next day acting up. Chased the spiking/ fluctuating water temps and loss of coolant for quite some time until I narrowed it down. Hopefully, it's not your problem. Easy enough to pull your plugs to see if any coolant is washing them clean.
  Your story of the dude following you is freaking me out. What's up with that? I would've dialed 911 after 5  or 10 minutes of that nonsense. Did you at least get his plate number?
                                 Bobby

[harry s]

Sorry to hear you can't bring the LaSalle to the GN. Hopefully the problem won't be too serious and easy to find.     Harry

[KenZ]

Jon,
Almost exact scenario with my original 1936 engine. When you start losing coolant and running hot, other things just get worse.  I had a cracked intake valve seat and the cylinder had fluid in it when the head was removed.  The compression was low in the cylinder and the spark plug also indicated something was not right.  Hopefully you don't have a bad block but just a heads up on what to look for when you get home.  It can be frustrating but you will get her back on the road!  Lots of help on the Forum as you well know.  Ken Z                 

[Bob Schuman]

The 41-60S I bought in 2016 from a friend had a very expensive engine rebuild about 2001, ran several thousand miles with no overheating, ran18 months and about 1000 miles for me with no overheating, then one day ran noticeably hotter on the dash gauge, found to be one gallon low on coolant, first time ever. Coolant in cylinders 3 and 5, turned out to be cracks in the block that my very talented and experienced friend said appeared to have been there when the engine was rebuilt in 2001 without any crack repair efforts at that time.
My point is that cracks in these blocks may be present for a long time, then one day rear their ugly head and call for an engine replacement.
The car in question now has a newly built flathead with a perfect block, a new owner, and may be at the GN this week.
Bob Schuman

[LaSalle5019]

I had a bad head gasket that was causing a similar issue. I didn't notice any radiator foaming or bubbles when running, but when I forced air in each cylinder through my compression tester hose, I could hear a faint bubbling listening through the radiator fill with the cap removed on cylinder #1.  After removing the head on that side it was very apparent on the gasket and head surface where the seal was failed.

When I first discovered this I thought for sure it was a valve seat or cylinder wall crack as that seems to be most of the horror stories on the forum but it turned out to be a much simpler issue.  Hope yours is simple too.
Scott

[Bill Ingler #7799]

Jon:  To me it sounds like the prime suspect for your problem is the radiator. What do you know about the radiator ? Has it been re-cored? If coolant is not flowing down through the cooling tubes fast enough to cool, then you will see the temp gauge rise. Now throw in the wrong radiator cap,one that does not seal against the neck of the radiator, and you can loose coolant out the overflow. I have had radiator shops tell me I have good flow through a radiator yet have overheating when driving. I then have taken off the top tank on those radiators and found at least 50% of the tubes plugged. If you are going to take your car on a long distance drive make sure your radiator is in top condition for prolonged highway speeds.  Bill 

[z3skybolt]

Jon,

I am so sorry to hear of your difficulties.  You were off on a great adventure and I had been traveling with you vicariously.  Let's hope that it is something rather simple and not terribly expensive.  I'd be hoping for a radiator issue as and easy fix..

You put your LaSalle to the test....a long trip, highway speeds, summer temps.  She let you know that she needs some attention.  Let us know how it all comes out.

Bob R.

[39LaSalleDriver]

Latest update.

Went out and did some preliminary tests this morning and created this attached spreadsheet with all my temperature measurements. These were all done while idling after sitting all night.

To begin with, there are no coolant leaks visible anywhere. While I haven't seen a lot of overflow out of my tube when it gets hot, I have seen a bit, so hopefully this is where my fluid loss is happening. I pulled the dipstick and everything looks normal there (no "milky" appearance). Will probably drain oil tomorrow to verify. Pulled every spark plug and found nothing out of the ordinary there, certainly no evidence of water/coolant. Coolant appears to be circulating in the upper tank. No bubbling of coolant in the upper tank. No cavitation of lower hose (new hose and spring inside) observed. No white smoke from tail pipe.

Everything certainly looks "normal" to me at this point. I didn't take it all the way to "HOT" because I was having difficulty getting it to that point   It seemed to want to hover at the 3/4 mark while idling in the driveway for about a half hour. I was able to get it to go up to say a steady 7/8ths point by driving it around the neighborhood (doing about 35-40 mph), but I didn't have the time to devote to being shut down on the side of the road for an hour while it cooled down from "HOT".

One interesting observation I had while driving it though, was that I got it to just shy of being "HOT" but it just stayed there. It didn't go higher or lower regardless of air flow through the radiator. Normally, the route I take for testing would have easily brought that down to the halfway mark considering the ambient temperatures (72 degrees), speed limit (35 mph), and circumstances (flat, shaded road with little traffic). Offhand, that would seem to imply to me a water flow problem.

I am wondering if the problem is one I read about on this forum somewhere in which the shaft is slipping on the impeller of the new water pump I got from Kanter. At slower RPMs all appears normal, but as the RPMs increase the slippage becomes more severe. I've also seen the recommendation that the shaft and impeller be tack welded to avoid this which I am sure the one I got from Kanter did not have.

I think for my next round of testing, I will check compression readings, drain the oil (it needs changing anyway) to check for anything funny there, and perhaps a combination of a combustion leak test kit, a radiator pressure test, and leakdown test.

Have I missed anything?

At this point I'm really hoping it is the new water pump which is the problem and not a blown head gasket or worse. Not that it counts for much because I don't know squat about what has or hasn't been done to this engine prior to my owning it; but I have made it a point to chicken out and shut it down just when it gets to the "HOT" mark and let it cool off for a while before proceeding. I'm not a fan of watching steam fly out of my engine compartment.

Your story of the dude following you is freaking me out. What's up with that? I would've dialed 911 after 5  or 10 minutes of that nonsense. Did you at least get his plate number?
                                 Bobby

No, but my friends Smith & Wesson had his number if needed 

Jon:  To me it sounds like the prime suspect for your problem is the radiator. What do you know about the radiator ? Has it been re-cored? If coolant is not flowing down through the cooling tubes fast enough to cool, then you will see the temp gauge rise. Now throw in the wrong radiator cap,one that does not seal against the neck of the radiator, and you can loose coolant out the overflow. I have had radiator shops tell me I have good flow through a radiator yet have overheating when driving. I then have taken off the top tank on those radiators and found at least 50% of the tubes plugged. If you are going to take your car on a long distance drive make sure your radiator is in top condition for prolonged highway speeds.  Bill 

Good advice, but right now I just don't know. Like the engine, I don't know what has or hasn't been done to it prior to my ownership. I do however, have the correct cap on there. I will say (and perhaps ignorantly so), that I can't imagine the car running like a top for 10 hours one day and having no overheating issues, and then the next day a semi-plugged radiator causing it to overheat almost immediately when I get it on the road. That just doesn't make sense to me, but I am by no means an expert.