1966 Chevy impala 400 small block running hot, wants to overheat

my impala while idling likes to run at 225 degrees so in this video i switch out the lower under drive pulley for a stock size pulley, it took the engine down to 200 degrees

[@josephmclovin9763]

Bro- you need to pull your heads and make sure those later 350 heads are drilled for the steam holes that are specific to 400 engines.

[@charlesnorris2993]

yea, reg heads that are not setup for the 400 need to have the steam holes opened up, also, new thermostat, good but specialy on the 400's, add a 1/8" drill hole on the outter rim of the thermostat, for air bubbles to easier pass + also add's a teeny bit more flow, my old cheyenne with a 400 i did 2 1/8 holes but my heads was original for the 400. also probably going to get some hate but not sure what temp that stat is, but if its a 195, try to find a 180. never had an issue with mine even in 112F temps outside.

[@doctorcountersteer6580]

Love the 400! That hooker is really talkin!! I see you got some Vortex heads on her- So if you don't have one already in it, try a thermostat with a by-pass hole or a weep hole. If you have both of your fans hooked to the same temperature switch they should be divorced to where one comes on first say at 195 then the second at maybe 205 or 210; but you will need a 195 t-stat. And also if you are running antifreeze or a mixture of it, it does not transfer heat as well as plain water. Since city water is generally loaded with calcium chloride, the chloride portion of it is pretty corrosive; especially in a system containing both ferrous and non-ferrous metals. To avoid that, always just run distilled water in your cooling systems. Forgive me if I'm wrong but from my Keyboard Commando post, it looks like you are in Cali., somewhere. My point being that if your latitude does not see too very much below 32° F, I wouldn't even consider running anti; especially not with a 4 hundred sbc and let alone in an .030 over mill. Please keep us filled in. Btw- NEW subscriber here!!

[@Politically_Incorrect973]

Seen the first video on your 66 project and been watchin all the rest and had to subscribe. Working on a 68 myself and wasn't sure how the header panel comes off but your video was actually one that showed it. Good stuff bro keep it up

[@cali530marcos3]

Thanks, appreciate u watching

[@doctorcountersteer6580]

I forgot ALL about the steam holes needing drilled in the residing heads; a mandated need👍!

[@xpelon209x]

Having a fan shroud would be much better.

[@xpelon209x]

I'm working on my 70 monte carlo and i chose the fan and clutch with thermo. Instead of electric fans.

[@cali530marcos3]

Yea it looks kinda empty with just electric fans so imma do the clutch fan with shroud setup

[@perezm714]

@ 5:26 & 9:45 calls it a name. That's how I mechanic.. lol

[@johnsmithson2506]

Fan and shourd sounds like a great idea and it look like you had center bolt valve cover and 350 heads ? 400 small block had steam holes in the heads and blocks I like 400 small one of my favorite engine. Good luck with you fix .

[@jlpsuroeste]

Bigger Big Block 😁

[@ABs70nova]

When i was changing out my pulleys i was literally going back and forth the autozone probably like 10 times in a day trying out different belt lengths. Because one would be to short or the other one barley to long. Lol i ended up with at least an extra 8 belts that ive now had in my trunk for years haha

[@cali530marcos3]

Yea it was stressful because everyone trip to the parts store took like 45min and I wanted to get it done that day

[@TheKaisler]

Bro you have a nice set up; engine and the inside engine bay area. I have my alternator on the driver's side also. I didn't think I could put a power steering pump set in there. I'm glad you made this video. Keep up the good work. I push a 1963 impala coupe hard top with a 327 under the hood. Also I like your roller motor, I once rebuilt one of those in my garage adding roller rocker arms arm as well. I live in Stockton, Ca. What city are you representing, if you don't mind me asking?

[@cali530marcos3]

I stay in woodland, ca about 40min from Stockton

[@eliasalmada5156]

@@cali530marcos3 what's up g

[@racer67]

U need to put the original fan back on that spins with the motor and a shroud and u will be fine.

[@cali530marcos3]

@@racer67 I went back to a stock fan but still haven’t installed a fan shroud yet, but it does stay cooler

[@racer67]

@@cali530marcos3 i have 2 1967 impalas a black 4 door hardtop 396 turbo 400 and it needed a fan shroud to stay cool but i also have a green 4 door sedan and it has a 283 powerglide and it stays cool without a fan shroud it is an all original stock car nothing has been changed from the purchase from the dealership im the 2cnd owner only thing i changed after buying it is maintenance tubular control arms and all new suspension and a quick ratio steering box but i put an aluminum radiator in it and a new thermostat and just with the stock fan no shroud it stays cool,,,glad to hear u got it cooled down u got a nice one all mine are 4 door versions i love the 67 impala i always wanted a 2 door 67 bcus i love the fastback on them but any 2 door impala from the 60s is sweet n you got a nice 66 i daily drive my green 67 wich is why i upgrade the suspension cus i like them to drive n handle like a hondas rack n pinion if u ever want ur 66 to handle like a new car buy the quick ratio streering box from cpp it has rack n pionion internals n it makes a world of difference, that with the tubular control arms it makes it feel like rack n pinion steering its insaine the difference absolutely no slop in the steering what so ever🇺🇲

[@75yanez]

I have the same setup went with a Fan shroud GM clutch fan same radiator. temperature stays at 165

[@cali530marcos3]

That’s my next set up thanks for the info

[@mnuckles5948]

When can we expect another follow-up video!? I enjoy the project and you give me ideas on my '66 Impala

[@cali530marcos3]

I’m editing one right now, took it to get the exhaust done

[@kingswood2149]

Steam holes drilled in heads? My 400 stays at 180 but smokes white out of breather only no smoke out tailpipes any ideas

[@cali530marcos3]

Yes the heads haven the steam holes drilled, I was thinking maybe the under drive pulley was spinning the water pump too fast, I’ve been thinking of going with a fan and clutch assembly with a fan shroud to see if it stays cooler

[@josephmclovin9763]

Oh- sorry, just saw this

[@ronnelson7828]

That aluminum billet pulley spins the water pump slower, not faster.

[@edspaetzel8836]

Am working on an overheating 400sbc as well. Bored 0.040. looking to cool it better.

[@cali530marcos3]

I took off my electric fans and put a mechanical clutch fan, also with the stock pulley it seemed to help it stay cool, now all I need is to install a fan shroud and it should be good to go

[@jerseyshoreweldtech424]

Love your videos brother, reaching out from Jersey Shore 👍 Question on headers.. my 65 impala with power steering and 283 .. I saw 1 video that you finally got the right header.. which on was it ?

[@cali530marcos3]

It was a non hugger header, I think the brand was headman, there’s another video were I got the exhaust done finally

[@flodrummer100]

what a beast !!

[@cali530marcos3]

Thanks

[@1979royalknight]

If your temp sensor is in the cylinder head it will read hotter than at the thermostat housing.

[@cali530marcos3]

Really, well I guess it makes sense since that’s where the exhaust gas’s comes out of, there’s a port on my edelbrock manifold that’s next to the housing, I’m going to try that one

[@adrianlorence4384]

Saludos desde la cd de Mexico comentarle q no hay respuestos como los q le esta colocando a su chevy, se batalla por q nuestro mercado es muy escaso aqui debe de hsber solo 3 chevy del 66, un numero para contacto

[@T500cal]

If it applies, what vacuum port is the distributor advance routed to? Ported or manifold vacuum? Having it to manifold should help it idle with a bit advance, idling cooler. Worth a try

[@cali530marcos3]

I have it on ported vacuum, replacing the lower pulley and adding a fan clutch fixed my issue

[@user-david6265]

Simply put zinc in your oil and take the thermostat off

[@ryanmuir6338]

Given that you have enough initial advance, overheat at idle, not enough fan, overheat on the road, not enough rad

[@cali530marcos3]

Doesn’t really overheat anymore, but I think a clutch fan and fan shroud should really help it out and keep it cooler

[@tonyv1791]

@cali530marcos3 are you going rewire the car with a kit?

[@cali530marcos3]

Yes, I bought a new wiring kit from American autowire like 6months ago, im just waiting to install my exhaust system and also I want to paint the inside of the car

[@davidlenz6]

It seems to me the pump would spin faster with the larger pulley?

[@mickangio16]

You are correct.

[@jamesseekford4928]

Calling parts on your car a whore is the most relatable part of this video lol

[@cali530marcos3]

Haha, yea pretty much

[@adrianquirino6223]

Have you checked the heat cross over under the intake did you block the ports properly

[@cali530marcos3]

The edelbrock manifold I installed didn’t have that option since it’s a high rise intake, but I’ve been driving it and it seem to be fixed

[@joshpinedo4996]

Hey man! do you know heads those are by chance?

[@cali530marcos3]

No, they are center bolt valve covers so I’m guessing tbi, they probably just drilled the steam holes out

[@Turner.1]

I wouldn't have it without a fan on the pulley and cowl

[@cali530marcos3]

Yea, going to be putting a clutch fan on there and adding a fan shroud

[@Turner.1]

@@cali530marcos3 lots of guy throw the Kowloon away,but it helps to cool the engine by at least 15 degrees,and thats alot considering the combustion temperatures

[@JTsMechanicShop5748]

What oil pump are you running in that engine

[@cali530marcos3]

It’s a high volume low pressure pump I got at summit racing,

[@joshuagarvey9362]

Why put a smaller motor in?

[@joshuagarvey9362]

Love the 400 sbc.Biggest motor.

[@dsgaragedavid1987]

What engine size is this

[@cali530marcos3]

It’s a 400 small block Chevy bored .30 over so now it’s a 406

[@robertoibarra7209]

Since you are having problems with it just put an Ls1 problem fixed ! hahah

[@joshlepley1306]

A smaller bottom pulley would make you WP turn faster and essentially cool better. A larger pully slows it down. Wouldnt it? If you had the alt belt on diffrently you could have saved a few bucks buying a new one :) and a headache lol You also could probably have just used a long WP from the get go since you have electric fans and all the extra space. Lining up pulleys on a long pump is so much easier. If it has an electric choke, pumping it like that wont help it start (generally).

[@cali530marcos3]

It’s a manual choke but it’s not hooked up, and for the small crank pulley I thought the same thing, I thought it would cool better but it was running hot, then when I swapped out to a larger one it cooled it down like 10-15 degrees. I was thinking about switching the alternator to the other side too because it looks too empty on the passenger side like it’s missing something

[@joshlepley1306]

@@cali530marcos3 well dang. My setup is basically identical as what your doing. I havnt started the engine yet but I have a small crank pulley also. So ill have to watch my Temps to check that.. All my stuff is on the driver side also. It is alot but I figured with the space on pass side I can mount some AC someday and even out the look

[@mickangio16]

Bigger crank pulley spins the pump FASTER.

[@lordsauto]

I hate that.. almost ,, ugh..

[@cali530marcos3]

but then again when are we really satisfied with something, there is always something