two new radiators in 2 years

[Yan]

Hi lads,
I'm the proud owner of a 96LTD XJ.
I've installed 2 new radiators in the last 2 years (probably around 15000kms) both of which started leaking from the core. While I did skimp out and bought the plastic ali radiator (2nd one on warranty), I feel like they shouldn't have failed so quickly.
Before sinking more money into it I was wondering if anyone knows of any underlying issues that could cause the radiator to fail? I did replace the head gasket just before replacing the first radiator, and put a new radiator cap on (16psi I think). Could I have messed up the head gasket job which in turn is now causing the radiators to fail?
Happy to hear any advice

[FRANKIDOWNUNDER]

Is the radiator bursting or just leaking from pinholes? Bursting is usually a sign of too high a pressure which would be very unusual as radiator cores are designed to withstand quite high pressures. Pinhole leaks are usually caused by corrosion, but not usually that quickly. Poor quality coolant or no coolant, just water can cause this. so can use of caustic cleaners in the cooling system. Just checked my parts catalogue, 16 psi cap is correct. Did you buy it as an OEM part or just any old 16 psi cap as some caps are a different height in the neck section and too long a one will put extra pressure on the seat, thus raising the radiator pressure. Mackay Auto give a part number of RC 1008 as the correct cap with dimensions of 25mm from top of cap to bottom seat and a seat diameter of 38.5mm. Might be worth checking these dimensions as a wrong cap can sure give you trouble.

Hope this id of help.

Denis.

[eksjay]

Cut your losses, order an OEM Mopar radiator. You may get 8 years service out of them like I have been averaging since buying my car New in 1995.

I had two well known Nationally distributed after market rads installed a few years ago in succession, the second was installed shortly after the first separated on the drivers side tank under warranty. Same happened to second one. Total elapsed time of this inconvenience was 4-5 months.

Have been running my Mopar trouble free following the aftermarket experiment. Not saying this is true for all aftermarket rads, but you know what you are getting with Mopar. For some reason, these plastic rads endure.

[Yan]

Thanks for the tips.
Denis, I think the cap was OEM, but will double check the specs as you provided. Both radiators developed pinholes though which has me leaning more towards bad coolant than the radiator cap. I did use a coolant system flushing additive after I did the head gasket replacement, though I thought I flushed it out properly...
Eksjay, You might be right.. buy it nice or buy it twice seems to apply here.

[layback40]

The cleaner you used is probably the problem. Cleaning it out of the cooling system is dificult. Probably 3 or 4 flushes with tap water & then a flush with rain water is needed. Probably a good flush with tap water without the additive would have done what you needed. You have not mentioned the coolant brand you used. If you diluted it yourself, did you use distilled/rain water or just tap water? Did you flush the heater seperate to the engine?

[Yan]

It's been a couple of years since I did the flushing, so not 100% sure. I think I followed the instructions on the additive which were add it to the old coolant, run the engine to flush everything. Drain and discard, flush, add new coolant.

I've been running the Nulon green, which I probably diluted with tap water.

But I suppose we have found a likely culprit, and sorted out my next weekend plans at the same time!

[Classic Boy]

Do a voltage test of the coolant you possibly have a stray voltage path through the radiator which causes rapid electrolysis and which often leads to early failure.