Musical Doc wrote:So I have heard and also seeing in skylinechild's post that plastic radiators ARE designed to fail in the event of a over heat condition. My question is what causes the overheat condition that makes the radiator fail? How I see it is that the plastic radiator fails which leads to the overheating. That was my logic for buying a metal radiator when my plastic one failed. An explanation would be appreciated.
1 yes plastic radiators are designed to fail in case of an over heat condition.
they designed to blow out to vent the excessive heat and pressure that build up.
so your question is - what causes an over heat condition that causes the radiator to fail?
keep in mind an over heat condition is simply defined as an unwanted build up of temp and pressure.
an over heat condition can be caused by -but not limited to
1. fan failure - failure of cooling fans to turn on - coolant gets too hot and well....blown radiator.
fan failure could be due to another electrical issue like a bad temp sensor or as simple as a bad fan relay in the relay box. ( nissan IPDM relay issue anyone )
2. not enough coolant in system - simple and straight fwd- run it dry and see what happens.
3. mechanical failure - ie water pump / thermostat fairly straight fwd.
4. hose failure - hose gets a leak...coolant that has a high temp and pressure escapes... not enough coolant in system...and well.... failure.
5. incorrect / spent coolant....- fairly straight fwd - coolant that is incorrect for your car or coolant that has lost its cooling properties.
6. age of radiator - face it its plastic not adamantium - its only soo much heating and cooling cycles plastic can go through before it gets brittle and breaks & will need to be replaced.
ADONI wrote:I think by the plastic radiator design to fail, is a preemptive warning to you, knowing something is wrong with the cooling of your vehicle. Now there is also the possibility that plastic has a lifespan, before it breaks down and become brittle. Like in my case last year, where the fan bolts on the radiator, developed a hair line crack.
I went back with plastic, cause it looks neater/original that the metal one. Also, when I was changing mine, I saw a guy with a metal one, that developed a leak and had to get it repaired.
correct on preemptive warning. and also correct on plastic has a lifespan. theres only soo much heating and cooling cycles plastic can go through before it gets brittle and breaks. the same holds true for rubber hoses.
some manufacturer recommend every 2 yrs you replace coolant and thermostat and every 4 yrs you replace coolant thermostat and water pump along with hoses.
the serpentine belt is replaced every 3 yrs or 100,000 kms or so.
the bolts that hold the fan in place is a typical issue with plastic radiators - develop hair line cracks and well the fan doesnt fit directly on the radiator and over time may cause damage to the radiator or fan... or both.
if you take a look on the newer cars you'll see all around the radiator and stuff they have Styrofoam inserts
the inserts do two things
1. help channel the air through the radiator
2. help hold the radiator in place sturdy to prevent any excessive movement
which could otherwise cause the radiator to flex- transfer that flex onto the fans bolting points and well....the hair line crack.
in your case Adoni i would have taken it one step further and inspected the rubber grommet bushings that the radiator sits into.
if those bushings are bad or worn out the will cause the radiator the flex and move slightly and well since the fans are usually bolted to the radiator thats the anchor point and will bear stresses....and well.... over time.. you get the hair line crack.... as i said.... its only soo much heat plastic can take.
Metal Radiators also develop leaks... face it welders are not 100 % perfect.
i have yet to see a local radiator shop do an x-ray on a welded / brazed radiator to verify the integrity of the weld / braze so it will happen from time to time they get it wrong....
metal expands when heated and if you add pressure of a hot liquid the liquid will target the weakest point of the radiator - usually the weld / braze... and leak from there.
some metal radiators are just poorly built and instead of fixing just go with another metal one.
how much cars have to seen with radiators with weld spots in different locations looking like brass spots all over ???