Thread: Temperature spikes in 4BD1T

Ok.a recovery type radiator cap has 2 seals,so when the cooling system heats up coolant is pushed out through the cap into the recovery bottle,as the system cools coolant is drawn back into the header tank.Its the same as lots of jap cars etc use.When you check the standard system the header tank will always be down a bit,because of expanding coolant,this way when you check the header tank it will be full and no air pockets which can upset sender units and thermostats,also pockets of air can cause corrosion in the cooling system.Most parts suppiers should be able to supply a recovery type cap to replace the standard cap and a plastic overflow bottle.Hope this helps. Jim.

Did you get a solution for your problem with temp and loosing coolant ...mine does exaxtly the same as you have described .

This is my bypass set up dougal is this ok sort of looks like the heater is a bypass too the heater never gets very warm....just drove to work 27k after filling coolant levels last nite I jury rigged a bottle under the over flow from the expansion tank checked it just now full 2.5 lt would have expected 1lt but 2.5 ..the temp gauge was all over the place to 50 to 90 thermostats stuff it only a couple of months old too

I read through this thread with interest and unless I have missed it, no one has yet mentioned having the radiator cleaned ("rodded").

Over the years and with various vehicles this has proved to be a very positive thing to do for me, it addesses unknown potential problems as well.

If you have a tame radiator repairer nearby and you take it into them they'll take the top and bottom off clean it, and refit the tanks and retest for (I guess) less than $100. They'll also do minor stuff like straightening bent fins and painting it on completion.

While it is out of the vehicle you can give the whole system a thorough flush.

For the water component of the new coolant mix I have only been using rainwater, because depending on where you are tap water can have lots of lime in it.

Apologies if this reads like "teaching to suck eggs" but it didn't seem to have already been covered here yet.

Originally Posted by Adrian18

Did you get a solution for your problem with temp and loosing coolant ...mine does exaxtly the same as you have described .

I never found the cause of the problem, but as long as I have the radiator cap undone to the stopper the temperature is stable. It does use water, but not enough to worry too much about.

Cheers, Murray

On my isuzu I never had temp problem but itwas using a smal amount of water. When I looked into it the pipe inside the header tank that pulls the water back to the motor when it cools was broken off. A small piece of copper pipe soldered in fixed it. If you ever need a new radiator at any stage as the are near impossible to find in god nick and if you do they have a crap chinese core, ask PWR. I got one for mine so they have the template now. Not everyone likes alloy radiators but they made mine for a not much more than a recore and they got it powder coated for me. Very helpful people.

Well since I'm leaving on a trip tuesday 4 days away I took the radiator out and took it to get cleaned it turn out the tanks on both sides were half full of cememted crud...mmm so it got recored $775
I had 50km of fine driving then 1 spike but it been fine since so buggared if I know

Well looks like the new radiator did the trick we're just driven up from hobart and waiting from the boat at devonport .she drove great and temp was stable