: 425 knocking noise



ramon
05-13-04, 08:24 PM
i just bought a 78 caddy deville with a 425 and the old man i bought it from told me about the knocking noise he said was caused by his wife getting the oil changed at a fast lube place and not priming something, he told me he thinks the oil pan needs to be replaced. i am new to the world of caddy big blocks and would really like some advice. also, does anyone out therte know where ican get a rebuild/overhaul kit for under what autozone priced theres at, in other words under $600. just someone please let me know how to get this big beast up and running.

bryan1970
05-14-04, 01:41 PM
i'm also new to the cadillac scene and have a deville with a 425. and guess what mine makes noise too. but mine is more of a ticking noise. but any way. i know that there is nothing to prime on the 425. What viscosity oil is in the engine when it is making noise? Because i bought my deville off a guy that had the oil changed at a quick lube place and they put 10W40 in it and that is too thick of oil. I changed mine to 10W30 and it got a little quieter. How many mile are on yours mine has 127K. I have narrowed my noise down to the front lifters. and it is sometimes loud enough to sound like a knock but it is just the collapsed lifters. i have also noticed that it gets alot more quiet as the engine warms up. If it is lifters making noise try draining the oil and running the engine with ATF in it for a while. also be sure to change oil filters before and after you do that.

ramon
05-14-04, 03:50 PM
hey thanks i will have to try putting a different type of oil in it this weekend and i did here running atf was good but someone at work told me to mix it in with the fuel (3/4 cup). but i also heard at work that it may be the front lifters, how much is that gonna cost me in time, price, and effort. but atleast today she is legal to drive down the road so i am happy she now has some plates. also have you found a rebuild/overhaul kit for this car at a decent price like under $500?

bryan1970
05-15-04, 10:37 AM
Don't put ATF in with the fuel!! I don't know who told you that but that wouldn't help anything. The only reason ATF is good for running in an engine is because it has a high detergent level and it can sometimes clean out oil sludge that may be blocking the lifters. One other thing you could put in with the ATF is Marvel Mystery oil. I know the name is cheesy but it also has high detergent and could help clean out the engine. But remember all this oil changing will only get the noise to go away if it is a lifter making noise. any thing else like a rod knocking will require a rebuild atleast. I have not found any rebuild kits for the 425 but that is mainly because i have not really looked for one. Not sure how much it will cost to get the engine rebuilt but if you are thinking about just putting in new lifters you have to get a new cam shaft too. because the lifters and cam wear together and if you only put new lifters in you run the chance of breaking a lobe right off the old cam. especially since GM made a lot of bad cams in the late 70's and ealry 80's anyway.

ramon
05-15-04, 05:13 PM
would you happen to know where i can find the lifters and cam? and what are we talking price wise, i have found a few rebuild kits, but nothing under $600 i wasnt able to work on the car today since it wont stop raining (i hate ny) and i dont have a garage but hopefully tommorow will be better and a better work day.

JTraik
05-15-04, 09:15 PM
Hmmm... I also have this ticking noise in my 472. I was told by many people it was the collapsed lifters but not to worry about it? I have seen this mystery oil at the store...someone was talking about it but i didnt really pay attention. So can i just pop a quart of this in with my other oil and voila?

The ticking isnt very consistent...somedays it wont be bad...when im a little heavy with the foot it comes back....but for the most part it just ticks.

bryan1970
05-16-04, 06:47 PM
I think i saw a cam kit which came with a cam, lifters, and a new chain and gears on the auto zone website but i'm not 100% posistive. you may want to try out Maximum Tourque Specialties or Flashcraft. I have heard of people talking about these companies before. Maybe it was the MTS website that i saw the cam kit on.
As far as just adding a quart to your oil to get the ticking to stop it might work. infact i think that is waht the bottles directions say. but i have had the best luck with draining all the oil refilling with half ATF and half Marvel Mystery Oil and letting the engine run for about an hour. I wouldn't want to drive it much with it in there but it might not hurt to hold the RPMs up just a little above idle to get the oil flowing a little better because on a 425 the oil pressure max is only like 10psi!!! then drain out all of the mixture then refill with new oil and a new filter. And if your lifters only make noise sometimes some of the lifters may only be partially blocked and could easily be clearned out.

tripleyellow78cad
05-16-04, 07:29 PM
That sounds like a good thing to try,
my 78 coupe deville's 425 has some lifter noise as well.
Just after we bought or cad in 2000 we changed the oil and used to
heavy a weight of oil (straight 40W + stp oil treatment)
:fan:
and my engine has had lifter noise ever since then:dammit:
we tryied useing marvels mistery oil and it did help some what
but over time and using 10W30 oil you do not hear the noise
very ofter, useually it only makes noise after it has not been
driven for a few days, or when it is very cold out

but this engine runs damn good , damn reliable, s#&t gas mileage
though (8-12 mpg in town)(10-13 mpg on the freeway):wtf:

well i hope this helps

bryan1970
05-17-04, 10:28 PM
for the lifters to make a little bit of noise after sitting or when it is cold is actually a pretty normal thing for any engine. they tick after sitting because the oil has leaked out of all the lifters and all of it is down in the pan and has to get all they way back through the engine. And when it is cold the oil is thicker and does not flow as quickly as warmer oil. In the winter it might not be a bad idea to go to a lighter weight if you are going to drive the car every day.

my 425 could only dream of getting 12mpg in the city the best i have ever gotten was 9.5mpg and that was only on the first 1/4 tank!

and even with the lifters ticking a bit it runs like a champ also strong enough to lay down 30ft of rubber!!!:D

lux hauler
05-17-04, 10:32 PM
low oil pressure and engine noise....? I'd be getting it looked at before driving it any more.

cadillacdeville
05-17-04, 11:42 PM
Ok I gonna say this one more time since its a diffrent thred the noise on the 425 is not collapsed lifters or anthing machaincaly wrong with the car the 425 selected by the cadillac motor car division was one of 300+ engins tested to replace the 500 the noise comes from the lifters being hydrolic and the use of less than 91 octane fule which is what the car is supsosed to run on to help with the clicking noise use 10w-40 valvoline high mileage with a can of engin restore with csl you can find it almost any where its next to the mystry oil at wal mart and will also help restore engin compression. you can email me at cadillacdeville@aol.com if you have any questions concerning the 425.

bryan1970
05-18-04, 08:17 AM
when i got the car it had 10w40 in it and was clicking all the time not just on start up like most hydrolic lifter cars. and i cahnged it to 10w30 because i heard that 10w40 was too thick of an oil and now the clicking nearly goes away once the engine warms up. and i thought i read in the owners manual that the engine is supposed to run on 87 octane but i could be wrong about that

cadillacdeville
05-18-04, 04:15 PM
Well, is it a constant ticking while your driving or is it more around 30-50 while your putting on the gas if so I would strongly suggest putting the highest octane gas you can get and either a fuel system cleaner or an octane booster. that higher rated fuel will burn hotter and faster and should stop that noise if that fails I sugjest making sure that there is nothing lose on the engin.

tripleyellow78cad
05-18-04, 07:19 PM
for the lifters to make a little bit of noise after sitting or when it is cold is actually a pretty normal thing for any engine. they tick after sitting because the oil has leaked out of all the lifters and all of it is down in the pan and has to get all they way back through the engine. And when it is cold the oil is thicker and does not flow as quickly as warmer oil. In the winter it might not be a bad idea to go to a lighter weight if you are going to drive the car every day.

my 425 could only dream of getting 12mpg in the city the best i have ever gotten was 9.5mpg and that was only on the first 1/4 tank!

and even with the lifters ticking a bit it runs like a champ also strong enough to lay down 30ft of rubber!!!:D
for the lifters to make a little bit of noise after sitting or when it is cold is actually a pretty normal thing for any engine. they tick after sitting because the oil has leaked out of all the lifters and all of it is down in the pan and has to get all they way back through the engine. And when it is cold the oil is thicker and does not flow as quickly as warmer oil. In the winter it might not be a bad idea to go to a lighter weight if you are going to drive the car every day.

my 425 could only dream of getting 12mpg in the city the best i have ever gotten was 9.5mpg and that was only on the first 1/4 tank!

and even with the lifters ticking a bit it runs like a champ also strong enough to lay down 30ft of rubber!!!:D
i wish my cad could do burnouts like that, maybe iam not flooring in enough
and that was a type-o I ment to say 10mpg in town:crying2:

also i use 10W30 yearround in this 425
and i only use 87 octaine fuel and I have no problems
and again my 425 will run great very reliable i wish cadillac would have used this enging longer insted of downsizeing is to a 368:banghead: witch is still a sound engine,
or going to thay gutless piece of sh!t (sh@t) HT4100
these were good engines(425) and more people should use them.
I talked to the guy at MTS(wisconsin) and he said that these engines can be made to hold their ground pretty well(300-400 hp) (300-400TQ) :burn:
thats very good #'S

hope that helps:)

lux hauler
05-18-04, 09:11 PM
compression from the facory is rated at 8.2:1.........87 octane should be fine.

bryan1970
05-21-04, 02:55 PM
techniclly the higher octene fuel burns slower. And i know that the 425 doesn't have enough compression to need that high of octane fuel. Plus the rating of the octane on the gas wouldn't have anything to do with lifters making noise. if the timing on the engine wasn't correct or if the compression on the engine was high then low octane fuel could cause spark knock but it wouldn't make the lifters make noise.

be careful flooring the engine all the way when trying to do a burn out beacuse it could stall the engine when the secondaries on the Q-Jet open then the tires wouldn't be spinning fast enough to use all the extra fuel and could actually flood the engine. Ask me how i know? because i've done it:D the first time it happened it scared me because i thought i blew the engine or something. The best way to get the tires smoking is if there is some wet or damp pavement then power brake and once the engine is at it's peak RPM durring the power brake start slowly leting up off the brake and one of the tires will start spinning. the POOF smoke. By the way usually my right rear tire is the one that spins. when you end the burnout that is when you have the best chances of stalling the engine. it stalled on me when i abruptly le off the gas but the best way to end it is to let off the brake and let the tire slowly grap traction. Also if one tire is spinnign and the speedo says 30MPH that one tire is actually going 60MPH because the speed doubles due to the gear reduction of the pinion gears(spider gears). Have fun!!!!!:coolgleam