Black Slime Radiator

[Ron H]

Engine was just completely redone and tricked up a bit nothing too radical. A huge price tag for the work. I drove it from the shop back home about 5 or 6 miles and noticed the motor was running hotter than I recall it used to trusting the gauge. I thought maybe a new sending unit could be a variance. Well, checked the fluids and noticed a collection of black slimy residue on the bottom of the radiator cap and around the opening. I'm fearing oil penetrating into the cooling system, poorly installed head gasket or something worse. On the other hand hoping for something less dire.
Anyone encounter this and have ideas on the problem(s?)
Thanks.

 

[HawkRod]

Sometimes shops will put some stop leak in the radiator to handle small leaks (Like Barrs), but what you describe sounds to me like oil. Maybe it got in there during the rebuild when the radiator was open to the environment, or it could be a head gasket problem.

From the perspective of higher temps: I am assuming you have a fan shroud still - these are critical to helping a radiator work like it should. However, the higher temps could also simply be a tuning issue. If the timing is off, for example, the engine can run hotter.

Since you had a shop do the work, I would bring it back to them immediately and let them know your concerns.

 

[Ron H]

did a cooling system pressure test and after a while it dropped and noticed coolant leaking fast underneath. Come to find one of the water pump bolts was out about near to 1/4". ok interesting find; but this isn't related to oil in the coolant far as I know. Seems as though one of the pump bolts enters a water jacket but not oil...

 

[coloradodave]

Ron,
First off, a newly rebuilt engine will run a little hotter until all the parts have had a chance to run in together. Your best friend there is a laser temperature gun (cheap at Harbor Freight). Point it at the thermostat housing after the engine is fully warmed up to get an accurate read. You can also check the radiator's function by pointing it at the top (the hottest temp) and then gradually moving down the core. It should progressively read cooler as you get toward the bottom.
HOWEVER, I would not touch anything at this point and call the shop who did the work tomorrow. Tell them what you found on the water pump and ask that they have the car towed back to their shop. If you start working on it you may have to accept responsibility. Hopefully, they will comply and then you can ask them about the black goo. Good luck to you.

 

[Ron H]

yes - did temp check with laser and temp stayed fine but this was idling not driving. See some bubbling sporadically in radiator. Also agree not to do putzing until the shop responds or I'd expect a reply. I'd like to think this isn't a serious problem but the symptoms here don't have an easy fix far as I know...

 

[Brandy]

Sounds like Barrs Leak to me. Seen it before..

 

[YY1]

Doesn't oil turn white when it gets into the cooling system?

I'd be very leery of a shop that puts bar's in a new engine- just fix the leaks correctly.

 

[Brandy]

YES

 

[Ron H]

A complete engine rebuild and need for this Barr's ****? That's a new one on me...here's a pic a little out of focus but you can see this slimy stuff on bottom of the cap, around radiator opening and a glob in the coolant. This is after I cleaned it up and took it for a 10 mile drive, have to imagine this stuff is building like plaque throughout the system...motor has under 25 miles on it!

 

[Brandy]

That happens when the Barrs leak, or similar stuff is placed in the system while it is not up to temp. Should be used while the engine is HOT so the solution can travel to the leak and plug the hole. then solidify as the motor cools down. Put it in cold and it clumps up and coats everything because there's no heat pressure making the leak spew hard enough to flow the sealant to that spot..

 

[HawkRod]

A complete engine rebuild and need for this Barr's ****? That's a new one on me...

Actually a number of new car manufacturers use it on their new cars. For example, all new Corvettes do. Used appropriately, I have to assume it would be OK. Now if it is used to mask problems, that's another story...

I think a discussion with the builders is in order. My suggestion though is not to start with an accusatory tone - this is likely to just go down a rabbit hole in the wrong direction. Let them know what you have seen and your concerns, and allow them to respond to those concerns. THEN make a determination if you are pissed or not. Sometimes things happen that shouldn't. In my mind, what separates the good companies from the bad is how they handle question, concerns or problems when they happen. The good ones make sure things are made right. Give them that chance first.

Just my $0.02. Good Luck!

Hawk

 

[Ron H]

I appreciate the advice and think I'm handling it with diplomacy. My brother was an auto mechanic early in his life before making a career change and had rebuilt a few engines over the years back in his GTO days. I've done a fair amount of motor work over the years as well. His buddy, a retired mechanic, still does a lot of engine work. Both looked at my motor saying they've never encountered this situation after a rebuild. Long story, decided to pay this shop five figures to do the work so I could have it ready this summer while the car was undergoing body resto at the same time. My time wouldn't have allowed me to get this done for another year or so. The shop's reply so far "Normal residue after rebuild - drive it and enjoy it". If it is some stop leak additive, why would they need to add it and then not tell me they did especially after asking them what this globby stuff is? I have a septic tank where I live and tell ya my radiator looks like a septic tank. Motor continues to run hot that could be break in related; but not subsiding. From what I'm told it's running nearly 20 degrees hotter than it should...and what it used to run at. Complete with headers and a 3" exhaust system?

 

[Brandy]

I would take it to a radiator shop and show them. Also take it another engine builder and show them. Gather opinions from experts and then take it to the ones who built it.

 

[Brandy]

Oh, and check the temp rating on the t stat.

 

[Ron H]

Thanks sort of started down this track you suggest; my brother took the skanked up radiator cap with him a few minutes ago to have some friends who own a dealership try to assess what it is. As a fellow member posted, it could well be stop leak additive and if so must have dumped a whole lot of it in. It seems pretty definite the system should be flushed out and as mentioned look at thermostat. We noticed there had been some leakage evidence around water pump fittings and one odd fitting that looks jury-rigged rather than correct fitting. My brother surmised that the shop may have had problems getting them sealed and rather than drain out the coolant to repair or replace fittings, just tossed in stop leak stuff. If this would be the case that's better news than something more serious being wrong internally. This shop has a good reputation from what I know but for the supremo price tag some careless oversights: low pressure hose from pwr steering too short having collapsed hose, fuel line jammed tight against alternator bracket, and as mentioned a loose water pump bolt that spewed a leak.
What does $10k plus buy these days?

 

[Brandy]

Thanks sort of started down this track you suggest; my brother took the skanked up radiator cap with him a few minutes ago to have some friends who own a dealership try to assess what it is. As a fellow member posted, it could well be stop leak additive and if so must have dumped a whole lot of it in. It seems pretty definite the system should be flushed out and as mentioned look at thermostat. We noticed there had been some leakage evidence around water pump fittings and one odd fitting that looks jury-rigged rather than correct fitting. My brother surmised that the shop may have had problems getting them sealed and rather than drain out the coolant to repair or replace fittings, just tossed in stop leak stuff. If this would be the case that's better news than something more serious being wrong internally. This shop has a good reputation from what I know but for the supremo price tag some careless oversights: low pressure hose from pwr steering too short having collapsed hose, fuel line jammed tight against alternator bracket, and as mentioned a loose water pump bolt that spewed a leak.
What does $10k plus buy these days?

Hold their feet to the fire. Make 'em fix it. I would ask them point blank what they would think if were their motor they had just shelled out 10,000 for? Would THEY accept that? No reputable person is gonna answer yes to that question.

 

[The Rebel]

For $10K they should do a complete flush and then re-inspect + resolve any other issues for free. Easier said than done though. Be polite but firm. If they have a good reputation on the street they don't want their name getting out as being a chop shop and possibly lose business. Possibly a threat about reporting to the BBB as well as posting on social media to stay away might also help.

Good luck & keep us posted.

 

[RT K_line]

I agree with the above statements, be diplomatic but firm on requesting them to flush the system so you and they can see if it returns. If it doesn't then fine but if it returns then there is a problem.
Question, was the radiator gurgling by the time you got home. I mean when you shut the engine off. That would definitely tell me combustion gasses are entering the cooling system. I was an ase certified tech for 25 years and a master tech for 15 of those. With all that work the radiator should have been sent out to be cleaned and presure checked. You would hope the block was too in my opinion.