Cloudy Radiator Coolant (After Flushing)

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skylines225

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Hi guys, anyone familiar with this issue?

I have a rebuilt 273 small block on a '66 early A with an original 3 core radiator. I noticed the engine running slightly on the hot side, and a spray of coolant was left on all over the engine followed by a small puddle of coolant dropping from the bottom of the engine. I flushed out the radiator, and added new 50/50 coolant in case it was clogged with too much stop leak.

While flushing the cooling system, the timing cover gasket busted at the top corner, causing antifreeze to spew out everywhere (hence the spraying.) I added new coolant and had the cover+timing chain/gears replaced, and sealed up. The coolant started to get cloudy right before the cover seal repair and again right after (by now there is all new coolant.)

A few weeks of driving around town, the engine runs better than ever, not overheating, oil is perfectly clean, but coolant is still cloudy. I know it may be easy to say it's a head gasket problem, but before we get into that, I would like to know some thoughts. Much appreciated!

Note: Months prior to this issue I had a brand new 4 core copper radiator installed, but one day it busted a large seam at the top edge opposite side of the hose. No warning or overheating. 3" busted seam. Nice radiator, but chances are it was a faulty one. Still suspicious however...
 
Sounds like your building pressure in the cooling system. Either from a crack in a head or blown head gasket. I would start with a dye test to see if exhaust gasses are present in your cooling system. A good radiator shop can perform this test for you.
 
Thanks, sounds like a good place to start! So pressure buildup wouldn't necessarily show up in the temp gauge?
 
It may be a small combustion leak into the cooling system that takes a while to build up enough pressure to vent somewhere.
 
That's interesting... could that be caused by the head gasket or could it be something else? Also, if the radiator cap is off during engine warm up, should the fluid stay at the same level, or would it jump out during each rev? When I was performing the radiator flush, that's how I noticed the leak in the timing cover was by revving up the engine. Every time I would move the throttle, it would spew out. I appreciate your help
 
Yes if it is getting pressure in the radiator it will boil out of the open cap. Depending the amount of the pressure as to how little or a lot is expelled.
 
Yep, it all makes sense. I'm now slowly being stabbed in the kidney with a sharpened head gasket!

The engine was well taken care of and professional rebuilt by the original owner around six years ago while only adding about 5,000 miles after the rebuilt. He knew what was up, but the car did sit for the majority of those five years. When I bought it last year, I replaced all hoses, belts, carb/trans rebuild, exc.

At this point would it be worth taking it to a radiator shop, or should I just get it repaired? My pops isn't around right now to help out with the big problems, so I'll have to take it somewhere. Thanks so much!
 
Does it have a trans cooler in the rad. if it is leaking the coolant will be cloudy. I would want to get it checked at a good rad shop and also get the 4 core rad fixed. Simple fix if it is a copper rad.
 
skylines225 said:
Yep, it all makes sense. I'm now slowly being stabbed in the kidney with a sharpened head gasket!

The engine was well taken care of and professional rebuilt by the original owner around six years ago while only adding about 5,000 miles after the rebuilt. He knew what was up, but the car did sit for the majority of those five years. When I bought it last year, I replaced all hoses, belts, carb/trans rebuild, exc.

At this point would it be worth taking it to a radiator shop, or should I just get it repaired? My pops isn't around right now to help out with the big problems, so I'll have to take it somewhere. Thanks so much!
Click to expand...

I would for sure have it tested to get a base line. Then you will know what direction to take.
 
Yes the trans connects to the bottom, I saved the coolant I originally drained. It looked like spinich pulp, I thought it was because of it having too much stop leak in it. It sat in a closed container. Now it's got that raw peanut butter look to it.

However, I reved it with the engine warmed up and radiator cap off. it didn't boil over. We'll see what the radiator shop says. Thanks!
 
The dirty radiator fluid I drained was caused by leftover stop leak in the system. The exhaust test came out clean (I rented a kit) However, one problem began immediately following the last posting:

The vacuum needle began to drop and jump back up to normal until the engine shut off. I was able to have it start and run nicely after properly setting the timing and inspecting all electrical. I noticed some white smoke (not steam) coming out from the exhaust during startup. The day was already getting pretty warm, and the smoke did not dissipate. This wasn't normal warmup steam. it wasn't a lot, but it's never happened before. The smoke lessened as the engine warmed up (did not drive it,) but it still had small amounts of smoke while revving and idling. The exhaust smelled normal.

It warmed up to operating temp without overheating and started right up several times, but once the idle screw was adjusted, the engine stumbled and went back to a continuous vacuum drop (no misfire.) I still cannot see through the radiator fluid even after replacing it.

Whether or not it is all related, I think it's time to take it into a shop. I hope this helps anyone with a similar problem. Any suggestions about going into a shop with these problems would be greatly appreciated!
 
I wouldn't get excited about a little cloudiness in the coolant. It takes many flushes to get it even close to clear and most store-bought flush today is wimpy. I bought 5 lb of powdered citric acid on ebay to use. You don't even know that the cloudiness is little bubbles. The one time I truly had a failed head gasket in a 1982 Dodge Aries (common problem), I got a "brown mousse" of oil floating at the top of the radiator. I ran it a whole summer that way. I drove 20 mi to work fine, but it would boil-over just as I got home every hot summer, so I just flushed in new water by jamming a hose down the radiator top.

I have not had an early round-top Mopar radiator that did not split the seam on the front side (opposite hose, like you). That is an endemic problem. Some shops knew how to solder in an internal brace to make them last longer. When you finally tire, a 22" wide square-top radiator fits, but check where you need the tubes, or go w/ a slick aluminum one, since work better and some are only ~$150.

If you really think you are getting combustion gases into the coolant, there is a test kit for that where you suck gas from the top of your radiator thru an aqueous solution that changes color if there are combustion products, or many shops use an old emissions probe. I got the kit from Cal-Vans but it never changed color. Don't recall if I tried it on my Aries, but no need since the oil was obvious.
 
Pull your spark plugs and see if any of them look like they are brand new, as in steam cleaned. If so you have a coolant leak in that cylinder.
 
Thanks for the vacuum gauge chart! All the spark plugs had a bit of oil and carbon. Coolant pressure test checked out normal, as well as the exhaust test. I'll look into a better coolant flush system. Thanks for all the help, I'm glad I was able to take my time with it and not rush to a shop right away
 
What helped a lot with the radiator running slightly to the warm side, was installing a fluid overflow tank and replacing the lever cap with a standard one (since it has an overflow hose, it works best with a standard cap.) Even a homeade tank works, I used a small empty juice bottle strapped to the fan shroud. I will flush it, but at least one problem is down.
 
Oh, no overflow before. Maybe backup. I think it is normal for a little coolant to flow into the overflow bottle and then get sucked back when the engine cools. That usually happens when people think the radiator should be filled to the brim. Original ones that didn't have an overflow were supposed to leave a little air gap at the top. Some people here keeping adding water to the rad to the brim, then wonder why their overflow level keeps rising. The system is just adjusting itself. That is why many owners manuals since the 1990's tell you to just fill coolant in the overflow and not even look in the radiator. In my 1980's M-B, the "overflow" is actually a pressurized "reservoir" and is supposed to have air at the top just like the radiator that it is effectively part of.
 
The raw peanut butter can be rust and other crud inside the water jacket. Or is can be old Bars Leak brand stopleak, or oil or trans fluid. If trans fluid, it ought to have a orange or reddish tint. As far as the exhaust smoke, if it is coolant, it will be moist.

I don't recall ever seeing cloudiness in coolant just due to a combustion gas leak into the cooling jacket. I would test the cooling system with a pressure tester if I suspected that; and, if you drive it for a while, that is when it is more likely to overheat.

I am betting you are just still getting the cooling system crud out; I rebuilt our /6 and had the block acid tanked, we flushed and back flushed the rad and heater core, and after 600 miles on the rebuild, the coolant is a murky brown, and needs a fresh change; so we are still cleaning out 40+ years of neglect. I expect you are too.
 
Thanks BillGrissom and nm9stheham, the coolant now looks more green and opaque, not really cloudy, but no chunky bits floating around. I'll still have to do a proper flush at some point, as long as it's not running on the warm side. As for the other problems, they went away once I replaced the spark plugs, distributor, and fuel filter. It could have been one of those going out, or a combination of a few.

It ran great until a few weeks later when It started to run as if it was stuttering and slowing down. When trying to restart the car, the starter was slow and the lights weren't as strong. The alternator was fried when I took it to get tested, so I switched it out along with the regulator and a recharged battery, its runs much better.

The vacuum gauge tends to read at a steady 10 at parked idle, so I might have to recheck the valve gaps and go from there. Thanks for the help and support!
 
Is that 10" of vacuum? That is quite low for a stock engine at idle. Do you have a moderately agressive cam in it?
 
nm9stheham Yes, I spoke to the guys that rebuilt the carburetor and they say the vacuum reading is normal since it seems the engine has a higher cam. That's why the vacuum stays between 9"-11" at normal idle settings. It does dance around a bit, but in a healthy way. It's been a bit of a guessing game, but it seems that most of these other problems were caused by it sitting for so long after the rebuild like how you suggested with the cooling system. It's a time capsule, but that's what's been part of the fun!
 
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