Thread: 3.5L rebuild?

check timming and fuel mixtures.
Drain water from radiator and fill it anti carossin anti boil.
Ensure car is on a good hill to refill so the rear bumper is lower then the top of the radator so it doesnt get airlocks and swich on the heater to as well.

Originally Posted by Bulldog

Thanks. I'll try that... What about radiator hoses? Change them? I've heard a small crack/hole can cause overheating...

why are they leaking . If not then why

Originally Posted by Reads90

The other problem with the fans on the front , is that they don't have any funnel system and only push air thought the rad that wants to go. Where as a fan on the other side would be in a couling and therefore force air in though the rad and therefore working about 10 times better

Could the elec fan be doing more harm than good (blocking the airflow).

Originally Posted by Bulldog

Could the elec fan be doing more harm than good (blocking the airflow).

in my mind yeah . take it off check the rad is not blocked . Ie you can see light thoughn it.

Originally Posted by Bulldog

Could the elec fan be doing more harm than good (blocking the airflow).

No it wont do anything to it. Every car with aircon has the thermo fan on the front so it shouldnt make anydiffrence at all.

You know there is an obscure but simple reason that old carby Rangies overheatthet is often overlooked.
The water vent from the inlet manifold, which is the highest point in the system, gets blocked and an airlock results.
Follow the hose which goes from the RH radiator tank to the middle of the manifold and check that the little steel pipe stub is clear. If not , get a drill and drill it clear with the drill in a pair of pliers. Do not use a drill unless you are really good as there is a water jacket there which is quite narrow.
A viscous fan has a fluid coupling like a torque converter. This enables the fan to be of a larger capacity than a straight steel fan, as the speed is governed by the slip in the clutch, to about 3K RPM.In addition they usually have a bimetallic strip , which closes an oil gallery and stiffens it up when hot.
Old Rangies also can get hot if the head gaskets are leaking into the valley. There can be no water loss, yet there could be large leaks. In this case the engine will be blowing oil out of the valley seals near the distributor. When I pulled my 3.5 down, I even found a burnt "gulley" in the head where the gasses had pushed through. The outside "short" headbolts cause this and should be deleted on fitting new gaskets , or only done up to say 20Ft/Lb.
Regards Philip A

Originally Posted by PhilipA

You know there is an obscure but simple reason that old carby Rangies overheatthet is often overlooked.
The water vent from the inlet manifold, which is the highest point in the system, gets blocked and an airlock results.
Follow the hose which goes from the RH radiator tank to the middle of the manifold and check that the little steel pipe stub is clear. If not , get a drill and drill it clear with the drill in a pair of pliers. Do not use a drill unless you are really good as there is a water jacket there which is quite narrow.
A viscous fan has a fluid coupling like a torque converter. This enables the fan to be of a larger capacity than a straight steel fan, as the speed is governed by the slip in the clutch, to about 3K RPM.In addition they usually have a bimetallic strip , which closes an oil gallery and stiffens it up when hot.
Old Rangies also can get hot if the head gaskets are leaking into the valley. There can be no water loss, yet there could be large leaks. In this case the engine will be blowing oil out of the valley seals near the distributor. When I pulled my 3.5 down, I even found a burnt "gulley" in the head where the gasses had pushed through. The outside "short" headbolts cause this and should be deleted on fitting new gaskets , or only done up to say 20Ft/Lb.
Regards Philip A

Thanks for the ideas. The 4 bolts are out (i've heard of this before). Is it a big job to replace my fan with the viscous type? Do they bolt straight on?

I would actually remove the water pump and check the impeller and the condition of the face behind the impeller for serious pitting etc. The impeller blades actually had broken on one of my 3.5's, causing BIG overheating problems, so much so that I thought it had done a head gasket at first.
It'll cost you about an hour or so with an early rangie engine, and about $6 for a gasket.

Also, if you are running SU's still, get some one who knows about them to balance and set the mixtures, and possibly even fit richer profile needles, that way you can run more spark advance without detonation, and it should run cooler under load too.

After market cams aren't always the problem, it is the way they are fitted/ timed that can cause a problem. If they aren't dialled in correctly then a good cam profile will become useless, causing poor vacuum and torque etc.
I have had good results with Dynotec PC216 and the higher lift PC217 cams, and you must use decent lifters with them, NOT holden ones.

Furthemore, I had rangies over in the west, and I clearly remember driving for long distances with a full load in my old '81 and on a day that was reaching at least 50 degrees I had no cooling issues. Infact the only overheating problems I have ever had was with a blown head gasket, and with that broken water pump I mentioned. As the engine is ally, it will cool very efficiently anyway, and the Rad is well big enough for a small engine like this. I don't think they are renowned for inherent overheating really at all, except maybe in the UAE or Saudi Arabia etc.

JC