1938 66S Overheating (some)

[Daves1940Buick56S]

I know this is a much discussed topic. And I know the ultimate fix is to remove the radiator, recore if necessary, and pull freeze plugs and clean the block out. But taking the hood off in my car is a pain, so I am hoping to maybe dodge or delay the bullet.

 

My car is not grossly overheating. In fact in cooler months it does fine. But on warmer days, like above 85 degrees F it slowly creeps up, especially in around-town driving. And it gets so hot under the hood that the corn gas boils and I have vapor lock issues. I did find my fan belt to be loose, tightened and it certainly helped with the charging and some help on the cooling but not much.

 

Here is the situation:

1. I still have my splash pans and they are installed

2. Radiator top tank gets to over 200 deg F. Temp at bottom around 170 deg F, maybe a bit higher. This is on 89 degree day.

3. My cap said 7 lb but it was not holding pressure at all. I replaced with a new Stant. Apparently my radiator is not original to the car as the neck depth is different so I had to go thru the Stant cap specs until I found one that fits. Cap now holds pressure but will start spitting out coolant once it starts creeping up to 200 deg. The radiator seems plenty big enough, top tank is well over 4 inches wide so it must be 3 row. The guy I bought the car from said it was a truck radiator but that could be RUMINT. (I did do a pressure test on radiator/block to see if it could hold 7 lb and no pressure loss even after 1 hr. I know original spec was atmospheric pressure only.)

4. Once the car gets hot the hood panels are almost too hot to touch. I just about burn myself getting them open.

5. I do have an Facet electric pump but it is installed at the back of the engine compartment. Original electric pump was 2.5 lbs so I replaced with 4.5 lb and that helps the vapor lock some - at least the boiling seen in the glass fuel filter at the carb calms down some when I cut it in.

6. I did do a basic flush and replaced hoses 3 yrs ago after I bought the car. I think I did the "2 sec drain test" on the radiator and it passed.

 

This is my plan:

1. Drain coolant

2. Put my bore camera into the radiator and see if there is scale buildup.

3. Isolate radiator from block. If scale do a CLR and reverse flush followed by Evaporust soak (maybe several times) followed by flushing. If no scale seen skip the CLR step.

4. Pull thermostat and check. If it still has bypass valve, remove and replace with freeze plug with 1/4" hole like I did on my '40.

5. Use bore camera to see how bad block is if possible.

6. Do CLR/Evaporust like above.

7. Normalize, install Gano filter and road test

 

Notice I don't have "pull freeze plug" on the steps above. I am going to try to avoid that but may not be able to depending on what I find. The engine/chassis is very clean, almost show clean so I am hoping the block isn't too bad.

 

Question: Should I pull off the splash pans? The air flow seems pretty restricted with them in. I also have them for my '40 but have never installed them.

 

Wish me luck, Dave

[dibarlaw]

Dave:

 As I was the one who recomended the flushing I did start with CLR (MUCH CHEAPER THAN EVAPORUST) as recomended by others. IT did not seem to give noticable results. But I may not have given it enough time. Again, the shop I took my 37 to indicated that they pulled the core plugs and cleaned the block. I also paid their bill to have the radiator cleaned by West York Radiator and all was pronounced clean! With this confidence we struck out for South Bend in 100+degree temps in 2013.

 As long as I could keep the car below 50 MPH it would not go up to 212 deg. It boiled over on me 3 times on the trip out.

 Every few hours of or so was needed to find shade and raze the hoods.

Less frightening and cooler on the Pre-War after tour and the trip back home. I believe we did over 2,400 miles. It seems like things stabalized.

 We drove the car for over a year with out overheating issues. Then when we started out to the 2015 Springfield BCA national. We only made 57 miles over the mountains leaving Chambersburg on route 30 and what was left in the block plugged up the radiator solid. Embarassing rollback ride home!

 A 1938-41 on our 36-38 tour of Nashville had the same thing happen. His brakes seized up causing overheating then the engine gave up its sludge to pack the radiator. When I checked it for him the top tank was solid with rusty mud.

[Wayne R]

Dave, just incase  you have not heard about this.

Its called -- Evans high performance waterless engine coolant--, now i have never used it , but alot of 

my Buick friends in Sacramento CA used  this when i was living there,  and still to this day in there  classic old Buicks.

Rather than me tell you about it  just go on line and google it.

It has one problem its not cheap,---but it lasts the life of the car.   regards.

[EmTee]

2 minutes ago, Wayne R said:

Evans high performance waterless engine coolant

 

On the downside, it is less thermally efficient than water/glycol.  From what others on the forum have said, it appears the average coolant temperature is higher when using Evans.  Bottom line: the coolant system needs to be clean and tight first.

[Wayne R]

2 minutes ago, EmTee said:

 

On the downside, it is less thermally efficient than water/glycol.  From what others on the forum have said, it appears the average coolant temperature is higher when using Evans.  Bottom line: the coolant system needs to be clean and tight first.

Yes  Emtee  you are correct  re   clean and tight   , but owning and driving 36---41--- are  some of Buicks most

restricted  models for air flow, i know as  restored and owned a 39 in New Zealand in 1979 its in a cool area

to live in . and like Dave says, getting to freeze plugs,  removing, radiator, and  hood is a real----job.

 

 

 

[EmTee]

Yup, I get it.  My point really was that with the price of Evans coolant, the last thing I'd want to be doing is continually 'topping-off' the radiator every time it pukes on the ground.  Also, if overheating is an issue now, Evans would only exacerbate the situation...

[Wayne R]

Best of luck  Dave---hope you  get  it running, to your satisfaction.

A photo of my 39  fisher body, was first in class at the International vintage car show,

 

in New Zealand mid eighties, notice that licence plate, was one of the  first personalized plates in New Zealand,.

sorry about photo ,no digital those days ,photo of a photo.

Edited August 30, 2021 by Wayne R (see edit history)

[Mark Shaw]

Dave,  You have a good plan with one exception...  Make sure the timing is not retarded. 

 

I suggest that you first advance the timing just two degrees & give it a test run to see if it helps... 

 

I always try the easy fix first....

 

 

[Jim Nelson]

Hi Dave.     Welcome to the cooling issues on Buicks..   You have a ? non standard radiator ?     First,  that tells me a previous owner had temp. problems.    The 60 series and up had Buicks bigger radiator / cooling wise.   It was a 3" deep core.   The 40 series had the thinner 2" core.    I have a 38-46s and 35-58 .   The club I belong to has most of the members using a 'pusher fan'  in front of the radiator.    Next.  do you have a remote infra-red reading thermo.    I trust no one when it comes to these issues.    Next,  with the IR thermo.  I warm up the engine ie 160* gage.   Then I scan the back side of the radiator,  side to side and top to bottom.    This will give you a pretty good idea of its capacity / ? plugged cores,  area's not working.   Next,  I scan the rear of the engine (manifold side) looking carefully at the lower rear  part of the block where rust / sludge packs up.   Then continue forward along the exposed cylinders  looking for unusual temperature variations..    Then,  I'm guessing,  you will find warmer temps showing the block has got crap in that area.    If your able,  you can pull the rear freeze plug and scrap / dig out the crap in that area.   Vacuum  out as much as you can of the loosened rust.    Then replace that freeze plug.     I have used evaporust with some success.    I needed to. use three  passes and still got  very dirty up to  light brown coolant out.     BTW,   If you have a remote camera,  looking in the top of the radiator will help.     I live in Florida so engine temps are an issue.   I removed both lower shields to help with cooling.   Next,  using the remote IR temp.,  I check each exhaust outlet into the exhaust manifold.   That will tell you if you have an exhaust valve issue.    If you need to 'freshen up the valves' by pulling the head.  this lets you loosen up crap in the head and block  cooling channels all the while cleaning the lower block.      This is assuming this would make your cooling get better.     Remember,  these cars were designed to go 50 to max of 60 mph.     If this doesn't help,  its pull the engine time for a full rebuild, convert to insert rod  bearings mod's, etc.      I've been there and done that on both my Buicks.     BTW,  I installed over drive in my Buicks so I can cruise 65 mph all day long with 2350 rpm.    I also am able to use 'real gas' cause its available and runs better....      PM  if you want more details.    oldbuickjim@gmail.com   

[Jim Nelson]

1938  Buick model 46s  coupe 

1935  Buick  Model 58  Vicky

[1939_Buick]

5 hours ago, Wayne R said:

Best of luck  Dave---hope you  get  it running, to your satisfaction.

A photo of my 39  fisher body, was first in class at the International vintage car show,

 

in New Zealand mid eighties, notice that licence plate, was one of the  first personalized plates in New Zealand,.

sorry about photo ,no digital those days ,photo of a photo.

off topic

Car is no longer registered with those plates. My understanding is the car is still in CHC.  Plate history may have an error

https://www.carjam.co.nz/  shows as "MY1939 has never been registered.

[Wayne R]

Sorry ---NZ---i dont understand, my 39 Buick was sold with that plate, and it 

was registered, i know because i was Sales manager of a large GM dealership 

in Nelson, and i ordered that plate about nine months  before  i registered it ,

as i had spent about 2 years restoring it then.

I sold it to a owner in Christchurch,  with those plates still on , then i   moved to US 

about  2 years later.   Thank you.

[1939_Buick]

3 hours ago, Wayne R said:

Sorry ---NZ---i dont understand, my 39 Buick was sold with that plate, and it 

was registered, i know because i was Sales manager of a large GM dealership 

in Nelson, and i ordered that plate about nine months  before  i registered it ,

as i had spent about 2 years restoring it then.

I sold it to a owner in Christchurch,  with those plates still on , then i   moved to US 

about  2 years later.   Thank you.

I have sent you a private message.

[Daves1940Buick56S]

Thanks to all for replying! I have 1 vote to pull the pans and that has convinced me. Too bad - they look great and keep the engine compartment real clean but the price is too great.

No Evans for me, will stick with good old Prestone. Mark, I did check the timing. It's about 3 degrees advanced over spec of 6 deg. Jim, the car did have a pusher fan in the past. Trying to not go that route if possible. I did do scans with the IR temp gauge but will do it more thoroughly after cleaning. Wayne, nice car!

 

Update:

1. Found the info on the radiator. It is a Harrison 3109319. My parts book from 1942 indicates this is the correct one for 1938 series 60. So now I know which Stant caps are correct. I have numbers for 4 lb and 7 lb and will publish tomorrow.

2. While preparing for the drain today I noticed that the heater valve is on. Since I have the heater hose output and input on the thermo housing connected together temporarily this means I was pumping 200 degree coolant from the block outlet right to the inlet. A small amount but it cannot have helped. Will correct.

3. Drained the radiator and block. Flushing tomorrow, pull hoses, then look at the core top, then start the chemical warfare!

 

Cheers, Dave

[38Buick 80C]

you sure the bypass hasn't failed?

[Ben Bruce aka First Born]

33 minutes ago, 38Buick 80C said:

you sure the bypass hasn't failed?

 

I vote for #2 acting as a bypass in addition to the bypass.

 

  Ben

[MCHinson]

I would not remove the pans. I would find the real problem, most likely the bypass valve. 

[Daves1940Buick56S]

Further update. Pulled hoses and thermostat. Bypass valve is still installed. Spring seems weak to me. Will remove after cleaning the block.

 

Put bore camera into top tank. Pics attached. Not clean but not hopeless either. I will start with CLR, looks like plenty of scale.

 

Probably no work tomorrow due to heavy rain from Ida.

 

Cheers, Dave

Edited August 31, 2021 by Daves1940Buick56S (see edit history)

[Ben Bruce aka First Born]

You might as well bite the bullit  and pull the radiator. 

 

Ben

[Jim Nelson]

I agree.   Then when that is clean,  I'll bet the block needs evaporust run thru until the water coming out is fairly clean.    On my '37' I needed three kits to get it down to a light  brown color.   .     My opinion is at least minimize,  remove the rear freeze plug and remove what you can.       Its a pain doing that but it beats doing the whole system.      Buick designed their cars for 'normal' conditions.   Normal driving speeds around 50 to 60 but not all day driving we now think is normal.      I put up with 90+ * temps every summer and spend way to long at stop lights on black top roads waiting for green lights and the engines never get to cool down.    Does your car have a old Buick radio ?   mine weighs at least 50# or so it seams.    You have to get behind the damn radio to unbolt the hinge.    I got good at loosening up the 'hoop' and then actually twisting the sheet metal to let me pull the radiator.     Also,  removing the generator AND water pump to give you clearances needed in removal.      When its done,  you will be much happier and your engine will thank you.    

[Justinlb]

I had a really bad clog causing my engine to badly overheat, I ended up backflushing and blowing compressed air through the lower radiator and block hose (with radiator cap off)and it freed up the clog.

Then used evaporust and drove it around a bit then flushed it. Now my car doesnt go past half on the temp gauge no matter what.

 

What came out looked like slimy chunky chocolate milk

Edited September 4, 2021 by Justinlb (see edit history)

[Jim Nelson]

keep using evaporust until the water coming out of the radiator AND  the block is only a light brown.    I think you have lots crap still moving around and will settle down and create hot spots.     Do you have a remote reading infrared thermometer ?   (try harbor freight )    I recommend getting one and keeping it around to check things like leaking exhaust valves (checking temps.  at the manifold leaving points).    Its one of my favorite instruments to keep my Buicks running smooth.    

[EmTee]

12 hours ago, Jim Nelson said:

Its one of my favorite instruments to keep my Buicks running smooth.    

 

x2!  I recently used mine to fine-tune brake adjustment on my Riviera.  After going for a test drive each wheel reads within 5 degrees of its mate on the opposite side.  A super-handy (and inexpensive) diagnostic tool!

[critterpainter]

In regard to the timing, make sure the vacuum advance is actually moving the breaker plate.   Buicks have a bad problem of having the 3 bearing the the breaker plate rotates on wearing divots that wont allow the timing to advance with vacuum increase.

 

[Daves1940Buick56S]

My distributor is a NOS one from the late 1940s that I picked up a few years ago. I replaced the 3 ball plate with the more modern one with the plastic runners. I have a spare Dyna-Flyte 880 that I will install sometime over the winter.

 

Nothing to report, just letting the Evaporust soak in the radiator. It's in the low 70s here so have to give it time.

 

Cheers, Dave

[Daves1940Buick56S]

BTW I forgot to put out the Stant numbers for the radiator cap:

 

Stant 10228  7 lb

Stant 10208  4 lb

[Lawrence Helfand]

My 41 320 Century has never overheated and I do drive it regularly here in Nashville's hot summer. I had the radiator re cored with a modern design core which works better then original. My bypass valve was cleaned and spring refreshed. My lower splash pans are still in place but have considered removing them to reduce heat soar under hood after a drive which leads to elevated temperatures and manifold cracking as well as high fuel evaporation leading to vapor lock. I do not have a pusher fan but did replace my original with one from the Summit catalog which has more blades and moves more air at low speeds and idle. I am lucky to have never needed a block cleaning and attribute that to proper fluids drained dry storage when decommissioned in the 1960's   The cooling system design is not flawed and when clean and maintained works fine.  Modern cars are designed to sit in traffic on a hot day for hours with the AC going and the sun beating down. They have to and its a rare site to see an overheated car even in the south. Prewar cars are not designed for these conditions but that said should if water jacket is clean and free of debris be able to drive all day long on the highway without issue. Oil water and block will only reach operating temperature and length of trip has no relevance to overheating. My Buick runs a lot cooler then my 49 Ford flat head V8 with its 2 water pumps which did not tolerate sitting for long before the finger tapping of the temp gauge would begin. Even when new our vintage cars could never meet the needs of a modern car and many owners manuals suggest pulling over and cooling down the motor as if overheating is to be expected at times. We have less tolerance for technology imperfection today. If you want a cooler running vintage car get a vintage truck! 

[Daves1940Buick56S]

Just an update. Chemical flush of both radiator and block complete - Evaporust soak time was about 2 weeks each. Reverse flushed with water as well for > 1 hour. Also injected shop air into the block drain to try and loosen up crud. Did not pull a freeze plug (yet!). The 160 deg F thermostat was tested and passed. Did the old plug-the-bypass-valve trick (left a 3/16" hole). Installed a Gano filter and refilled with a weak Evaporust mixture (2 qts) and have been running it and driving. Ambient temp is in the 70s now but it seems to be running fine. After a long run the top tank was only 180 deg F. I have been driving with a loose radiator cap so pressure is ambient.

 

I checked thoroughly with an IR temp gun. Results: radiator cores have uniform temp drop top to bottom. The left- and right-most cores are about 10 degrees hotter. The head checks uniform front to back. The block (measured at bottom of jacket) is uniform from the front to just before cyl 8, then drops about 15 degrees as you approach the very rear of the block. I assume this is due to debris at the rear of the block. I will temporarily lower the Evaporust soln level in a couple of weeks and check the filter. When I switch back to antifreeze in November I will redo the block temp test and see if any change.

 

However, during all this I did find my exhaust leak - loose muffler clamp! I wish they were all that easy.

 

Cheers, Dave

[Fireball8man]

Dave:

 

I add WaterWetter from Red Line Oil - 12oz bottle to the radiator.  I have used this product on many pre-war Buick for overheating problems.  I used it recently on my 1938 Buick Model 41 and the temperature dropped at least 15 degrees.  I use this product after cleaning & flusing of the system.  I also use/used Gano Filters in the upper radiator hose to trap any scale/debris/ on the Buick straight 8 engines.

 

Lawrence

[Daves1940Buick56S]

Yes, I will use Water Wetter when I put the antifreeze back in Nov.

 

Checked the Thermocure mixture coolant (2 qts) after about 50 miles and it was black. Drained, flushed. Got some grit out. Gano had grit but not much. Refilled and 2 more qts Thermocure. Will let it go until abt 5 Nov then will flush and refill with antifreeze for the winter.

 

Also removed splash pans. It was not trivial. Now I see why the mechanics of the day didnt put them back. The right side came out ok, but the left side required the stabilizer bar to be dropped and lots of manoeuvring to extract.

 

Since people occasionally ask for pics of the pans, here they are. For a 38 66S coupe.

[dibarlaw]

Dave:

On my 1925s the exhaust down pipe has to be dropped and subsequently the entire exhaust system for remooval of the left side splash pan.

The previous owner made a cut so that the shield coud be bent back around the pipe without it's removal.

[Daves1940Buick56S]

Update. Did 2 rounds with Thermocure. It worked pretty well, black after a few runs with the car. No overheating. Got some crud in the Gano but not a lot. I was just going to put antifreeze back in BUT...started getting quite a leak from the area of the water pump. Pulled the pump and found the small front freeze plug behind the pump leaking. I guess I removed the rust that was keeping it sealed. Sent the pump off anyway for a rebuild to Flying Dutchman who has given me good service on the '40 pump. Went to pull the freeze plug but the rust has it pretty much welded in there. It's coming out in pieces but it's hard to work on it with the radiator in there. So now I have to pull the radiator. This is like when you go to repair something on your kitchen cabinets and before long you are down to the studs. I have some questions on pulling the rad but will start a separate thread.

 

Cheers, Dave

Edited October 27, 2021 by Daves1940Buick56S (see edit history)

[Jim Nelson]

Done it several times.   I removed the cross brace next to the top of the radiator.    This opens it up.   I removed both grills so nothing gets damaged.   If I remember,  I removed both of the hood sections and the pivoting section so the top of the engine is now ready.   I then actually 'twisted' the front section to give me good access.    You might not have to do that because I had to move the radiator forward about an inch or so when I ( don't tell anyone ) installed a/c.    I live in warm Florida and driving around in the summer on black top streets is terrible at stop lights.      It works nicely.   Causes some interesting observations when I drive with the windows up in the summer.    With the radiator out,  have the top off for sure and get it super cleaned.   I ended up replacing the core section and replaced with the best so my cooing would be good.   Plus,  most of my club has a pusher fan upfront to help.       General motors did an adequate  cooling design BUT it was for cars that ran ~ 50 - 55 mph.    Not like todays 60 / 65 mph traffic with lots of time setting at LONG red lights with the temp gage slowly working its way up in the South.   Yes,  I did a bunch.   Check with the guys in your area to see (honestly) what works for them.         38-46s,   35-58   Love my Buick's.   

 

 

 

[Daves1940Buick56S]

Thanks Jim! Yeah it went smoothly today. Had to fight 2 bolts but otherwise came right out. Did not have to pull the alternator.  I also got the remainder of the freeze plug out once I had room to work. And...I found a present! Some goofball had previously replaced that plug and just pounded the old one into the cyl head and left it there. Niiiice!!!! I was able to get that one out too. Pics coming....

[Daves1940Buick56S]

Pics...

[Daves1940Buick56S]

My "present"

[valk]

Looks like a bran muffin…good work, Dave

[EmTee]

"Top O' the muffin to you!"

 

https://www.youtube.com/watch?v=_z9NyQnDdz4

[Daves1940Buick56S]

Dropped radiator off today.

 

On the new freeze plug. This is the first one I have replaced not using the rubber expansion plug. No room for that here. Any special sealant to use or just pound it in plain?

[MCHinson]

No sealant is needed.