I just bought an 86 vert with the worse gunked-up radiator the mechanic ever saw! He thinks it is a result of dex-cool being run low on water. He flushed it once, and that did no good at all. He says the block, itself, is clean. Just the radiator is gunked up. Any suggestions? I hate to spend the money for a new radiator, because mine looks fine, with no leaks. The car WAS running 185o max before I cleaned it, now the temp guage as well as the speedometer does not work. I guess that is a $700 fix, unless someone knows of a better cluster to use. I am open for suggestions. I don't want to spend $700 for a rebuilt dash cluster and have it last a year or two! I have seen a new cluster advertised for $1100, but I do not like the looks of it. It is black with white guages. Is there a better looking one to consider? Cynthia

 

Take it to a radiator shop and have them rot it out and then pressure check it. You should be good to go.

 

I asked my mechanic about RODDING it out, and he said they do not do it to these radiators. Is he full of it?

 

Maybe some else can varify, but I don't think you're supposed to run Dexcool in an open system like ours. A shop put Dexcool in my '88 a couple of years ago and it still has brown cr*p come up even after flushing and going back to the green stuff.

 

Plastic tanks a no go? Well i noticed Dewitts now sells an economy aluminum rad that is single row instead of 2 row.

http://www.dewitts.com/collections/c...minum-radiator

$355

Model: 1129084A (Single row) Deliveries start Mid-Feb 2013

Introducing our new single row radiator which features one 1 1/2" tubes. This design increases cooling surfaces by 50% over the stock unit. An excellent choice for the economy minded customer that wants to eliminate failures from plastic end tanks and gasket leaks. This unit use the same full size aluminum end tanks from our double row, increasing fluid capacity.

 

I had a tank crack on my radiator a couple of years ago. I bought a brand new one at NAPA for like $110. It is almost the cheapest Corvette part that I have purchased.

 

There was NO anti-freeze in the car when I bought it. But it apparantly had Dex-cool in it at some time in it's life. Now I have a new problem, and will start another thread.

 

You can back flush the radiator. They (used to?) sell a tool that screws to the end of a garden hose that has a schrader (tire) valve on it that injects compressed air into the water stream. You can zip tie a piece of bicycle innertube to the end of the tool and the bottom outlet side of the radiator. one of these could also be fabricated with a plastic hose nozzle by screwing a schrader valve into it. Works very slick. I have fixed many clogged radiators, and even plugged heater cores with it. Blast as much water and air pressure into it as possible. It will blow stuff out the inlet all over your engine, so run another bike tube from the top inlet to the ground. If you wanna see what comes out, run it through a towel at the end.

 

The temp sender is on the drivers side of the head between spark plugs 1 and 3, check the wire is connected and not broken somewhere.
The speed sensor connection is on the transmission at the extension housing under the driver side of the car, look behind the gear select cable and up toward rear of trans. Is a big round thing with an electrical connector connected to it.

The dash is very tough and rare to fail just like that.
Check the link below, a heap of information there to help you fix it yourself.

http://www.batee.com/corvette/dcrg/index.htm

The main problem with corvettes is they act like a vacuum cleaner on the highways, leaves, twigs, and small roadkill all get sucked up and get deposited between the a/c condenser and radiator

You can get screens see link.

http://www.ebay.com.au/itm/84-91-COR...item439d49a472

Coolant with anti corrosion inhibitors is a must to save your aluminum tpi inlet manifold from corrosion, change it every 2 years religiously or suffer the consequences. they can corrode thru or if you have alloy heads it gets even worse, not just replace head gaskets but buy new heads as well if it has been many years without corrosion inhibitors.

There are inline filters you can get to stop crud from engines blocking your radiator.. see link.

http://www.ebay.com.au/itm/BILLET-AL...item1e6ea278b6

Am sure you should have these available in the united states as well.

 

Other side on '86+

 

Or go to home depot and pick up a piece of gutter screen and save yourself $100.00.

 

That tool sounds pretty cool. Sounds like something I need after mistakenly putting Dexcool in my cooling system. Good for 5 years. Yeah, I'll go for that! MAJOR MISTAKE. My cooling system is still messed up 10 years later.

Prestone made a similar tool (except no control over the air pressure -- it just sucked in air and let the scrubbing bubbles do the work):

 

Believe me, I had my doubts. I used a laser temp gun on a radiator and measured the temps all around a clogged PT Cruiser radiator, and it was pretty much cold all around, it was barely circulating at all. After a backflush with the compressed air, it was within 20 degrees of inlet temps all the way across the radiator. I could have filled a coffee can with chunks of rust flakes that came out. I was totally sold on it after it unclogged a heater core. We know how much fun they are.

 

Greetings,

Are you still using the stock radiator or was it replaced with an all aluminum one?

Charles

 

ANSWER TO Cntroes:

It is stock. By flushing it twice, and leaving flush in motor a day, I managed to clean it up. Wouldn't you just know after the first flush the intake manifold started leaking? But my mechanic somehow got a wrench to tighten a couple of loose bolts, and the leak stopped. I think I will have him change the manifold & all the other gaskets before it, before another leak appears. COMMENTS PLEASE? Thanks for all the help.

 

It might help to tell us what city and state you're in. There may be a member close to you who could assist.

 

OK - You have a couple of issues that you need to deal with - you're working on a 25 year old car - these things go with the territory.

As for the coolant - GM uses Dex Cool on literally tens of millions of new cars - it works - Dex Cool alone is probably NOT the cause of the problems. However - Dex-Cool is not compatible with the old style coolants. You need to completely flush the old coolant out of the system before going to Dex-Cool if that's not what the car came with. If you don't thoroughly flush out the system - the two coolants will mix and you'll get muck.

If radiator flush cleared up the radiator - GREAT !!! However - that stuff (the flush) needs to be thoroughly flushed out before new coolant is added and the job completed. One of the "potential issues" with using the chemical flushes is that it can eliminate the little pieces of crud that are preventing leaks. SO... if car is now running cool - it would be a good idea to get the cooling system pressure tested. This is where the radiator cap is removed, and a pressure tester attached in it's place. The radiator needs to be topped off before you start the test. The pressure tester has a pressure gauge on it. With the engine off, you pump up the pressure until the gauge reads about 10 - 15 psi. You watch the gauge to see if the pressure holds or decreases. If it decreases - you probably still have a leak, and you check all the hose connections etc. till you find and fix the leak. It can take some time to track down the leaks if they're small. Most any garage has one of these cooling system pressure testers, or some of the chain Auto Parts stores (e.g. AutoZone) typically have them as part of their loner tool programs.


As other posts have suggested, it would be a good idea to get a hold of one of those thermal (IR) "guns" and verify that the radiator input (where the hose from the intake manifold connects to) is significantly warmer than the radiator outlet when the car is running. If it isn't - there is probably still a problem with the radiator flowing properly, and it may bite you during hotter weather.

As for the incorrect gauge readings - it's highly suspicious that the gages went out around when radiator work was being done. First check the wires are connected to the sensors. The coolant temp sensor is basically a variable resistor - where sensor resistance is proportional to temp. So if you were to pull the wire off the temp sensor and ground it - check the gauge - then unground it and check the gauge - (the gauge reading should be QUITE different) that will give you an idea if the sensor is the problem or it it's elsewhere (wiring or cluster).

Just hang in there and work through the problems one by one.

 

My 96 came from the factory w/ dexcool. Shortly after getting the car, genius me sees the antifreeze is low, I overlook the factory "dex-cool" only sticker and start dumpin in the green stuff. Welll, few days later, I notice the sticker and (not knowing what dex-cool was), Im like wtf? Go online to read up and start hearing all the horror stories of what happens when you mix the two and how corrosive and clumpy dex-cool gets over time. Well knowing mine had mixed now, I had to drain and flush eveything. Well, tried removing knock sensors and broke the head off the one on the pass side. That was a real treat to get off/out...especially with the placement of them(can you feel the sarcasm?). Then flushing the block...ugh! Looked like muddy soup comin out in clumps. Nontheless, Im now fully converted to the old school green stuff along w/ a new be cool radiator. Moral of story...read warning labels lol.

 

[QUOTE=Purple92;1583426725]OK - You have a couple of issues that you need to deal with - you're working on a 25 year old car - these things go with the territory.

As for the coolant - GM uses Dex Cool on literally tens of millions of new cars - it works - Dex Cool alone is probably NOT the cause of the problems. However - Dex-Cool is not compatible with the old style coolants. You need to completely flush the old coolant out of the system before going to Dex-Cool if that's not what the car came with. If you don't thoroughly flush out the system - the two coolants will mix and you'll get muck.




I've been running dex in my L98 for........close to 20 yrs? and no problem.
People that have these strange problems with dexcool are people that tried to short cut their flush and failed to pull the stat or run clean water thru the engine long enough to remove 100% of the green before adding the orange.
Dexcool was formulated to work in ANY engine, especially engines that have a LOT of aluminum in the system. I've lost a head due to electrolysis and its not going to happen again.As green ages it looses its ability to protect against electrolysis, corrosion and turning acidic. Dex guards against that. Dex also guards against the chemical breakdown of the coolant with its 5yr formula. I have never seen any brown stuff, rust or corrosion or anything other than bright orange coolant in my system.

Use whatever you like, but to bash a good product based on internet stories or someone that ya knew that had it happen that probably did a crappy job flushing...just ain't fair to all that did do it right and have had good results. I flush @ 2-3 yrs at most usually for some other maint issue, but it gets flushed and cleaned often. There has never been a problem and I'll continue to use dex because its safe, its a superior product that was designed for aluminum parts and because I do it right so there is nothing to worry about. If I did shiddy flushing and poured dex into what WAS a green radiator...yeah, I'd be worried too!

If there was something wrong with the product it would have been recalled years ago. The problem is with those that do not use it right and then try to blame the product over their mistake. Never seen that before, right?
IIRC there were some court cases filed over this and they were thrown out when it was learned that the products were mixed...like it says NOT to do. Right on the label...yeah, right there.Thats why/how they created that useless all-compatable coolant that mixes with anything yet does nothing to prevent boil overs...,but it blends with ALL colors ! ! !

Sorry if thats a little blunt but its the truth. There is nothing wrong with DexCool.

To the OP,

I would question your shop if they are telling you that you need a cluster. Who came up with that? temp guages have sensors and sensors have wires. These things MUST have good grounds. There are also some known faults that are easy to fix. Mine is coming out tomorrow for the common repair to the circuit board.

For a cluster to FAIL...that just does not happen. Shops sometimes FAIL to earn from legit repairs so they "find" new repairs to help....
Whats worse,. too many of these techs today have never been trained on this technology and their opinion is about as worthless as mine regarding brain surgery.

Radiators get rodded out (if all metal) or flushed every day all day. A new radiator thats stock is less than $100...and you can get all kinds of good upgrades for $200.
If these guys cannot handle a gummed up radiator...I'd suggest taking the car home and getting a couple bottles of flush, or a gallon of vinegar to pour in the rad and let it idle for a while...then FLUSH it for an hour. Its not a big deal to take the thing out and stuff the water hose in the fittings and force water thru it or fill it with liquid soap..anything will help.
BTW...you can get a rebuilt warrantied cluster exchange for $350...lots of places.

Curious...
you said that it was running 185 max BEFORE you cleaned the radiator?
if it was running that low, what was the reason the mechanic got into the radiator? 185 is nice...

BTW they do not rod stock radiators...they are throw-aways. Disposable.
Good luck with it! Sounds like you got it under control.