Overheating problem..Need major help.

[latham83]

Hey ok well I just got a new dss racing shortblock 306 , with thumper heads , gt40 intake, and alot of other bolt ons. I put in a new 180 thermo, new water pump from advance auto parts, and the stock radiator is only 2 years old.
When i first start it up from cold and let it sit..it will stay steady at about 190..
as soon as i get driving..on a more cooler night...like 60 out... it will bump to 195 and pretty much stay there UNTIL i come to stop for a long time, or idle in a parking lot for about 5-10 minites..it will slowly climb to 205-210 and something sounding like coming from below the engine starts KNOCKING. as soon as you pop the the hood, it will cool back down to 195 slowly and the knocking fades.
The knocking ONLY comes when it hits about 205..that is it...
i def. have a cooling problem...and probbaly cause the engine is tight and new, something is knocking cause of friction and heatinting up..clearances are tight.
I put in 20-50 oil and watter wetter for my coolant also....
What the hell is the problem here?
Do i need an electric fan? All i have is a flex fan that blows air towards the engine.

 

[TRWXXA]

I'm surprised you're getting that "knocking" at only 205*. You could be right about the engine being tight, though.

Try to eliminate other causes. Check the weep hole on your water pump. Maybe it's about to go tits-up on you.

It does sound like you could use some increased cooling capacity. A 3-row wouldn't hurt. I don't know how efficient the flex fans are. They might give up some efficiency for HP recovery -- things like the flex fan always seem to be a compromise -- so you'd have to make up for it elsewhere. Look around, there are 3-row radiators out there that are direct, bolt-on replacements for the stock 2-row radiator. They don't require any modifications to mount them. I have one, and the car runs a lot cooler. Wish I could remember who makes it.

If you want to go with an electric fan, make sure you upgrade to a 3G alternator (didn't see it in your list of mods). If you're unning your HVAC fan, on a hot night with your headlights on and stereo blasting, while just idling along in traffic, and your electric fan kicks on, you'll drain your battery pretty fast.

 

[latham83]

if my radiator cap is shot or is old...would it cause the problem i just explained???

 

[Stang8URMPRT]

Hey man. 205 degrees is not hot at all. That's about normal operating temp. I don't like when it gets that hot, but when I put my motor in, going from 8.5:1 compression to 10.5:1 compression made the temp go from 130 (with no thermostat) to overheating, like 260 degrees. I didn't have a fan shroud cause I didn't need one with the old motor. Well, I got a shroud, and an Advanced Auto Parts three core brass radiator and a flex fan and it will get up there still, but I have a Mr. Gasket pusher fan in the front to click on when it gets hot. Pulls it down. I was sitting in traffic today and I live in Florida... it was 90 degrees here... and it wouldn't go over 205-210.

Your problem sounds like you have too much timing in the motor. Try to back down the timing a little. That will help it run a little cooler and hopefully stop the knock.

Nick

 

[Mustang John]

I would think that if it was because of the cap, you would see it weeping or even overheating and dumping into the overflow.

What are you running for coolant? Straight water and water wetter? Water cools well, but antifreeze lowers the boiling point. Maybe some antifreeze would help.

Also, the knocking "might" be preignition from heat.

What is your base timing? if it is more than 14 you "might" try lowering it a bit and see if the changes the knock...

I also think personally that 20/50 is pretty thick oil for a fresh motor that is tight... I usually break mine on 30 weight dinosuar based oil and swap to synthetic 5/w30 after about a grand or. But, that is just "my" opinion. I'd like to hear more on that myself.

 

[latham83]

But its only set at 12*!? if i back it down anymore wont it run like crap.
should i run the car for alittle with my rad. cap off to see if it get bubbles out?

 

[Stang8URMPRT]

12 shouldnt, but what octane do you run in your car? Please don't tell me 87 octane.

 

[latham83]

lol no no..i put 93 in..94 whenever i find it...
yea its set at 12 now and like i said...ONLY knocks when it hits 205-210...then will fade away if i drive or open the hood...its def. a heating problem i would think? i was told it shouldnt get that hot....
im so confused...i mean should i get an electric fan or 3 row rad.? whats gonna be more effective. Def. dont have money for both. and im gonna need a 3g alternator with the fan too so...what do u think? if my rad. cap is 15 years old would it do this? not sure if it is but..

 

[latham83]

..

 

[latham83]

this sucks..i dunno if my thermostat is faulty or my rad. cap is bad or if its a bigger problem..its driving me crazy. i just tried to burp the system..i ran it in park for about 20 mins with the cap off...didnt see much bubbles at all....how do i tell if the thermostat is workign correctly?! i have a new 180 in there...at 180 the pressure in the hose kinda felt the same as it did before 180? it did get really hot tho, but could of just been from the engine...you could squeeze it pretty easily..is it suppose to get super hard? it didnt really seem to "stop" at 180 like it should..it kinda stops around 190 for alittle bit..then slowly climbs to 195, 200, 205 if you let it sit for a while...

 

[latham83]

some say 205 would be normall.but i dont think thats the case...it really hot under there..plus i HAVE to keep it under 205 because thats when my engine starts knocking/tapping!

 

[Stang8URMPRT]

Don't freak out dood! lol! Listen... First off, if money is an issue, I would get the three row radiator. Also, the hose will be soft when the thermostat is open or the car's not warm yet. So if it's softer feeling when it's about 180, it's because the thermostat is open and coolant is flowing. It will be hard if you shut the car off because it isn't flowing anymore and pressure builds because it's not able to dispense the heat very fast. I would first off try to retard the timing a little. Put it back to 10*. It won't be a dog at all, maybe a little slower, but better then detonating. Will it knock when it's just sitting there or under load? If it's knocking just sitting there, you have more of a problem then just detonation. Spark knock, aka detonation, happens under load. But like everyone else is saying, 205 degrees isn't bad. Just because you have a 180 thermo doesn't mean it's going to sit at 180 all day long. It just means the cooling system will start working at the temp. I have a 160 thermo and it still gets up to 205-210. Nothing wrong, just more power = more heat = you need a better cooling system. Hope it helps.

Nick

 

[HISSIN50]

ill toss out a few cents worth:
John, i agree with you on break in (unless the mill was built specifically 'loose') oil weights....

are you using a parts store stat? i went through this last year. get a MR Gasket 180. it is fully balanced, opens fully sooner and has a bleed hole...i had a parts store one (new) and within a week i swapped to the Mr G, and ran at about 10* cooler from that alone.

it is little things like that which add up to allow a cool system. why ask about your cap - get a new one! it is old. the pressure keeps the boiling point up. and, as John said, if you are not running antifreeze, do so. i like to run 40/60 (coolant/distilled water, respectively) in the heat.

how is your fan shroud situation? having it oriented with the fan blade properly is important. also seal around the shroud (weatherstripping)...

for bleeding: on a cold motor, remove the rad cap. park or jack it up, so the front driver side is higher than the rest of the car. run it. when the stat opens, you will see coolant flow from pass side to drivers side (lookin through the rad cap hole). note the temp that this occurs.
run it like this for a bit - if there is air trapped in there, it should come out (also make sure your heater is on full bore).

that is what comes to mind for now. good luck.

 

[HISSIN50]

oh yeah, for drop in (pretty much - slight bracket mods needed) 3 core radiators: AZ and Pep both sell 3 core HD units (made by Modine and GDI, IIRC). good units and under 150 bucks.

 

[latham83]

Ok anyone know of local places where i can get a Mr. Gasket 180 thermo??
Also what kind of electric fan should i get..what are the best and best FITTING without alot of work and modifications....

 

[plastic_cow]

Electric fans can come off T-Bird Turbo's I think they're just direct bolt-on (or, as some of you have pointed out, a Mark VIII has them in 'em too...)

 

[HISSIN50]

Ok anyone know of local places where i can get a Mr. Gasket 180 thermo??
Also what kind of electric fan should i get..what are the best and best FITTING without alot of work and modifications....

for the top question, i got mine from the local speed shop (10 bucks). Summit, Jegs, etc sell them too for the same price or less.

on your second question, eeeeewwwwwwwwww. that is like asking what the best clutch is. they will take some fabrication and dont forget the 3G upgrade (with some of the smaller ones, one can get by with a 2G, but i would not consider that to be the right way to do it). plus since you are having trouble keeping it cool, it will possibly be on a lot, which will not fly with a stock alt.

that said, the Mark VIII is the king of stang fans (CFM's). you need a huge alt and a good bit of modding for it. i have not considered new fans (Spal, Flexalite, etc), but im sure a lot of those drop in w/o much modding.

good luck.

 

[latham83]

OK check this out everyone...I burped the system...Jacked up the drivers side , opened the cap, and had the heat on full blast..it is at least 90* here today...it seemed to heat up alittle slower than if the cap was on? when it hits 180.., the fluid doesnt really flow at all until it heated up to like 190 or so...then u can see it like pooring and flowing in the rad. didnt see many bubbles come out..although the fluid did drop a bit. so ill fill that up with watter...is the fluid in ther suppose to flow like mad as soon as the stat opens? cause that wasnt the case....maybe its opening late? i dunno..help me out...
could my cap be bad..with me saying that it seems to heat up very slowly with it off rather than on...

 

[latham83]

was gona go over to autozone or advance to get a cap..the motocraft one i have says 16lb. so...what is a good name i should get? Stant? i seen they have one with a pressure release and one without..whats that?

 

[HISSIN50]

pressure release is to bleed off pressure before the cap comes off (to help being sprayed with scalding coolant if opened when hot). i run those (and that brand) and they seem fine. i replace them once a year or two anyhow.

your rad experience was like mine. not like a river or anything (more like a creek) when the stat opens. but the level dropped, which means you probably got some air out (unless the rad is up to the top, the air comes out of the upper hose and fills the cavity of air in the top of the radiator, so you dont necessarily see bubbles). but level drop is good.


another good thing to have: next time youre at wally world, go to the kitchen supplies and get a 99 cent turkey thermometer. i use it to check the temps of the coolant in the radiator (via sticking it in the hole for the cap). not necessary, but it helps to know the actual water temps when you see water start to move.

good luck.