Tag Archives: Leak

Wrecked Radiator Part I

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Picked this up on http://www.corvetteonline.com and thought I’d share this.

I remember as a kid taking an old radiator and make a design in the fins with a screw driver.  Yes…very artistic…I was.

by on March 13, 2012

Cars have come a long way from their roots as steam-powered horse carriages, but the internal combustion engine will always have an Achilles heel; overheating. It doesn’t matter how old your car is, all cars are susceptible to overheating, especially out on the race track where they can run at wide-open throttle for a long, long time. Nobody likes to see that temperature gauge start creeping up, as it could indicate any number of engine issues from a leaky radiator to a blown head gasket.

For such a simple-yet-integral part of an engine, there seems to be a million and one things that can go wrong with a radiator.

A good mechanic always starts by checking the simple stuff first, so for the purposes of this article we will focus on diagnosing a busted radiator. Much of what we discuss here can be applied to a broad spectrum of motorsports, as well as non-racing endeavors. When it comes to pushing an engine to its absolute limit though, there are few events as demanding or brutal as circle track racing.The Common Cause Of Corrosion Is You

The obvious first step to diagnosing a busted radiator is a visual check, inspecting for leaky hoses, loose fittings, and so on. Sometimes finding a leak requires running the engine; other times it can be done by just looking under the car. Checking and tightening all the connections is a great first step, but a leaky radiator is usually just a symptom of a deeper problem, and diagnosing why your radiator is leaking is a job best left to the experts.

That’s why we turned to Jason Danley of Speedway Motors to fill us in on some of the most common issues when it comes to diagnosing a damaged radiator. “The biggest things with radiators are internal corrosion and leaks, damaged fins and a clogged radiator,” says Jason.

Radiator damage can take on many forms, though the two most obvious issues are corrosion and bent fins.

“On passenger cars the biggest issue with radiators is that people don’t change their coolant enough, or at all. What it will do is actually corrode the inside of the radiator, blocking passages and restricting the water, preventing the radiator from passing water through the passages to cool it. I’ve actually seen that corrosion break loose from the radiator and spread to the water pump, intakes, and even the engine block,” says Jason.

If the corrosion goes unchecked, it can even eat away at parts of the radiator and cause small holes that will only get bigger over time. These small holes can be difficult to find via visual inspection, so Jason recommends using a pressure checker. “Auto parts usually have these, and you just put it in the place of a radiator cap and make sure your cooling system is holding the pressure it is designed for,” says Jason. “The pressure depends on the car and the radiator manufacturer, though it is common for radiators to hold between 10 and 12 PSI.” Again though, that number depends on the specific radiator.

Depending on the age of your car and the condition of the radiator, corrosion may or may not necessitate a replacement radiator. If you want to keep your radiator in good condition though, the simple thing to do is replace the coolant every now and then. “The general rule of thumb is to change it every two years at least,” explains Jason. “If you’re putting a lot of miles on whatever you’re driving, you’ll want to do it more often.”If you do find yourself with a leaky radiator caused by corrosion, you may consider using one of the many magical fluids claiming to stop leaks. “Those will work on pinholes on a radiator, or something like that,” says Jason. “The big thing with that is every time you change the fluid, you have are going to lose that stop leak, so you have to reapply it. And if you use too much, it cold plug up the system, preventing water from flowing through the radiator.” As we’ll see later, it is also important to ensure that you’re not causing a chemical reaction with whatever additive you put into your radiator.

Bent and busted fins like these can causing serious cooling issues.

Vacuum – Tune it up!

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Checking the vacuum on your old car is an important part of a thorough, but most of the average guys don’t bother, or don’t have the gauge.  Most often if you do have the gauge, you might not be exactly sure what the reading might be.  For the recorded I’ve never had a car where the readings were stable.  Normally you’ll get a fluctuating reading that move around.  Below are a few ‘ranges’ and what they may indicate.

Standard Vacuum Gauge

These are for V8’s only:

–  A good reading will be between 15 and 22 in. hg (a steady needle).  Closing the throttle you should see a 5 notch drop and reopening it should settle back previous span (15-20).

– If you get a reading where the needle has a swing 4-5 in. hg ethier side of normal, you are looking at a possible simple carb adjustment.

–  If the reading is higher than normal you need look at replacing your air filter or check to ensure your choke is not stuck.

–  Low reading would be fairly steady reading around 5 hg will have you looking for a vacuum leak on the intake/carb area.  Look for poor connections at the carb or any “T” or “Y” or straight though connection.  Baring that look for cracked hose.  You know I hate vacuum leaks.  I recently restored a 1984 corvette with the Crossfire injection set up.  Rather than chase down a single spot, I just replaced them all.  That was a lot of vacuum hose and tucked in some stuff spots.  But you are working on something bit older, like my 1970 Mustang, replace it all, it’s going to go back sooner or later, especially with the kind of temps we have out here in the Southwest.

–  If you get a reading that between 8 and 14 you are looking at a timing issue at the least to leaking piston rings at the worse.  Do a compression check for the leak and use your timing light before you tear it apart.

–  If the needle is swinging (unsteady) between 14 and 19 hg that indicates valve guide problems.  That going to be a valve guide problem.

Thanks for reading

Tim