Rad replacement

[Optimist]

Hi there Bongonauts
New member here. Very much appreciated all the information from you . I have a '95 diesel 4wd with AFT black over silver. Just noticed a small damp patch under front bumper and I can see seepage from around the plastic/metal lugs on the rad top. I've read enough on here about overheating so keen to sort this out! I have LC alarm which has not gone off and coolant loss seems very slight.
I have ordered a new rad from JAS and was wondering is it best to replace all the coolant or can it just be topped up after replacing the rad?
From what I've read on here it seems you can remove the old rad with little coolant loss?
Thanks in advance to you techies,
Optimist
Teddington

[stilldesperate]

Theres a bleed screw on the bottom of the rad, drivers side. You can catch the coolant in a bucket if you want to recycle it, however surely better to put new in, at the correct mix, then you know the jobs been done properly.

You will need to bleed the system afterwards, there's a fact sheet in the members area.

Not too difficult to do (about an hour to change the rad, and the same to bleed it afterwards).

SD

[daveblueozzie]

Depending on how old the coolant is, its better to replace with a good quality coolant , red carplan premium.with about 40% to 50% mix. If you can, also do a coolant engine flush, something like the FORTE brand of flush.
You might as well change the thermostat as well with a genuine one, cost about £17 don't get a cheapo one off ebay.
AND AS BEEN SAID EARLIER MAKE SURE YOU BLEED IT PROPERLY, WHICHEVER WAY YOU DO IT.

[Optimist]

Ok thanks very much. I was told the coolant was renewed last August but I guess for the cost it would be better to change it. I'm just a bit apprehensive about all that bleeding lark.
Would the stat be playing up then and be causing this?
Thanks again
Optimist

[sparkymik]

It's time for a new one mine went last year in the middle of The Radnor mountains and no chance of a replacment out there, had to pack up the camp and get flatbedded out back too Hampshire, the top blew off as we were on route back from a day out too Hereford the alarm saved the day, I fiitted a new one from the Bongo shop two days later and all was well but as I say get it changed ASAP!

Sparky

[daveblueozzie]

Ok thanks very much. I was told the coolant was renewed last August but I guess for the cost it would be better to change it. I'm just a bit apprehensive about all that bleeding lark.
Would the stat be playing up then and be causing this?
Thanks again
Optimist

I doubt the stat will cause the radiator to weep, but if your going to drop the coolant it makes good sense to change the stat, why go to all the trouble changing coolant and find out the stat aint working properly, then you gotta start again.

[Alacrity]

No the stat won't be causing your leak, the leaking rad is very common, mine did the same January 2010. It is as well to change the stat as it is a key component in the system & one that can give problems & it makes sense whilst the system is drained.

Again as has been said earlier don't be tempted to fit a pattern one, I fitted a Bluepoint pattern one last year when I changed the rad & was concerned when I fitted a overheat alarm - which removed the gauge damping (i.e. it goes up & down whilst driving as you go up & down hills for example instead of just staying at 11 o'clock), as to how high the gauge ran. I have just had to drain the system to change a couple of hoses so I fitted one from Mazda & the gauge now sits a good 3/16 - 1/4" lower & nearer the 12 o'clock position.

[Optimist]

Ok, decision made, thanks very much for all your help
Optimist

[Northern Bongolow]

i gently beg to differ on the stat causing the problem,it almost certainly is the problem.
a sluggish stat lets the system overheat slightly,and the pressure increases inside the system. the rad leaks at the top because the coolant is too hot coming from the top hose inlet to the rad,the increase in pressure does the rest.
check your top hose out from the head,i bet thats all soft and spongey too.

ill get my coat

[Optimist]

Many thanks for replies. Just cannot find a "How to.." on the stat replacement...
Is there one somewhere?
Thanks again
Optimist

[wonkanoby]

its only 2 bolts?

if you can do rad you can do stat

[rita]

i gently beg to differ on the stat causing the problem,it almost certainly is the problem.
a sluggish stat lets the system overheat slightly,and the pressure increases inside the system. the rad leaks at the top because the coolant is too hot coming from the top hose inlet to the rad,the increase in pressure does the rest.
check your top hose out from the head,i bet thats all soft and spongey too.

ill get my coat

Hi,
Would a malfunctioning PRV on the header tank not be more likely to cause this fault,if it blows off when required it should not damage the radiator, unless the radiator is already past its use by date.

[Northern Bongolow]

the system usually runs at about 0.5 -0.8 when healthy. when things start to go wrong,usually the stat,the temps and pressure go up causing( unexplained ) leaks.
this is still under the blow off point of 1.1 at the cap,so the cap doesnt usually affect things at this point. if the pressure raises further then that may be different.
the point you raise is good though,ive just made a cap tester,for both pos pressure and the neg pressure release and descovered that half my spare caps failed in one way or another.

just my opinion though