Overheating Red Motor

[mezzmo]

We put some in the bash beddie to nuetralise the pressure in the back to try to prevent dust - not a chance!! seemed like a good idea. The amount of air circulation is kinda like what you would get out of the end of a straw being blown in by a 150 year old with emphysema!!

I wouldnt trust em'

[Sammy]

lol im sure it is do-able, not sure how practical it is .....

[Postie Bob]

Maybe not a good idea if your driving in the rain either  .
Back to the drawing board...  .

[Warren]

Dave some suggestions

Flush the Motor out -

Get a set of welsh plugs, knock the old ones out, remove the water pump and get a high pressure cleaner and blast the shit out of the block - particullarly at the back end - replace welshplugs with new ones.

Check your radiator -

As Busy suggests test your radiator, and if it is one from the old slant 4 cylinder engines replace that sucker with one designed for a holden 6.

Check your thermostat -

Ensure it is opening at the correct temprature - replace if needed.

Check your radiator cap -

Ensure its the correct pressure one

Other tips

Look to get a fan shroud.

Replace the fan with a thermo one

Block of the grill to the sides of the radiator forcing the air through rather than around.

Mostly it's either the radiator or engine gunked up that will cause the overheating

Warren

[MaTTe]

Some good suggestions above.

The chances are that the radiator is blocked up with rust from the block, a blocked radiator will not cool efficiently.
If you have radiator tanks top and bottom rather than on the sides, the rust tends to build up at the bottom and stop the water being able to transfer. Cross flow or side tank radiators are much better in this respect. The block is highly likely to have rust in the bottom aswell and should be cleaned out, however is unlikely to be your biggest issue.

The calcium and lime build up you were talking about can be cleaned up with a bottle of radiator cleaner, I'd be using it prior to putting a new radiator in.

A shroud on the fans is one of the greatest things to improve the efficiency of cooling, elecric thermo fans are an excellent option to regain some horse power, however I recommend having some with shrouds and operated via a tridon thermo fan switch in the lower radiator hose.

For a 202 the vk cross flow radiator is an excellent choice, my hq as worked as it is, always stays cool. A Chinese copy of the radiator is likely in the $100 range and most are quite good in my experience. You will need to adapt it to fit I would assume.

I'm running a vx ss radiator with the correct fans, however it was more effort than most people would likely be willing to go to inorder to fit.
My fans come on for between 5 and 20 seconds at a time in hot weather at the traffic lights with a 350 and bugger all airflow from the front due to the front spoiler.

What temp range is your thermostat?

[Dave]

Thanks all, there is plenty there to keep me going for a bit, I wont get to it this weekend, but I am dropping down to 4 days work a week in April so I should then get some time to play. 

I thought about the suggestion to get a high pressure cleaner and blast the shit out of the block but to be honest I wasn't sure where I should blast.  I should have done that when the water pump was off.  I also thought about taking the welsh plugs out to see if the motor was gunked up as this was my initial thought of the cause, but I was a bit worried to do that  I seem to recall my brother taking some out of his kingswood once and that they were silver round plugs about 1 inch across but that is all I know of them.  Are they on the side of the motor under the manifold on a 202?  if so that sounds like a real pain in the arse.  I suppose I could go an look. How many are there is it 1 per cylinder, is it something a novice should attempt?

I have no idea what temp the thermostat is, I didnt notice any markings but it opened in boiling water.  I wouldnt have anything to test what temp it opened at, probably easier to get another one.  Similarly with the radiator cap, cant see anything that says but will take another look.

Sammy re 

just be careful with the long and short shaft ones, they usually require a specific water pump pulley

  the pumps are identical the only difference was the length of the shaft after the pulley, the longer one goes through the fan blade centre and sticks out the other side a bit, the shorter one stops 5mill past the pulley, it would be better if it went through the fan but the fan has 4 bolts that hold the fan central so it should be OK, the fan didnt wobble when the bolts were loose so it cant mount off centre.

I will start with the radiator anyways.

thanks for your help, I will let you know how I get on when I get to it.
Dave


 

[Gordon]

Some good suggestions above.


A shroud on the fans is one of the greatest things to improve the efficiency of cooling, elecric thermo fans are an excellent option to regain some horse power, however I recommend having some with shrouds and operated via a tridon thermo fan switch in the lower radiator hose.

MaTTe, I have always shied away from electric fans wherever possible using the old theory that it is just something extra that can go wrong, but am starting to rethink this now. I've just completed my V8 conversion and am currently running a 15 inch mechanical fan with a custom built shroud on a triple core aluminium radiator running Nulon premix coolant. On the open road the temp sits at a steady 175 to 180 F, bit in town she can creep up to 200 F and in real bumper to bumper stuff I've even seen 220 F . Once I am getting airflow she steadily drops until she is back around 180F, so my deduction is that my cooling capacity is OK but my fan pulling power is not that great. After seeing your post I'm starting to reconsider my decision.

[MaTTe]

Gordon, mechanical fans are generally a good thing aside from the fact they draw a reasonably significant amount of hp compared to the electric load of electric fans.

How did you make the shroud? The best way to optimise the flow of a shroud is to have a 30mm gap between the shroud at the shallowest point from memory, tapering towards the opening around the fan.

Another consideration is the triple pass radiator, by having the fluids change path repeatedly it multiplies the draw on the waterpump which reduces the ability for it to push water at low revs. You may find switching to a single pass is more beneficial. My radiator is single pass.

The next thing is to look at the range of your thermostat. Most recommend 180 degree Fahrenheit, the theory is that with a higher temp range on the thermostat it spends more time closed to allow the radiator time to cool the water. Personally I run a 160 f thermostat which basically means there is always water flowing once warm so may make the fans come on more regularly than they would otherwise, however they tend to run for less time this way.

With my setup I have had to drop my radiator lower down than would be ideal, so the height of the grill is only half utilised by radiator. This causes my fans to come on occasionally on the freeway for short bursts, however I have intentions to add some additional airflow to the radiator core down the track. The benefit is currently outweighed by the effort. Despite all this my motor stays cool since leaving it to its own devices with the tridon thermo switch

[Sammy]

ahh my mistake, i was refering to water pumps that are shorter or longer from the block to the mounting flange on the shaft ... this was to suit cars with or without a/c & p/s etc but thats different to the part after the shaft flange your talking about!

[Gordon]

MaTTe, I fabricated the shroud out of fibreglass after making a plug from an old Ford Falcon shroud that I modified to the dimensions of my radiator core. It has the shape that you describe. Yes, I'm running a 180F thermostat. The radiator was originally in my donor van which also had a 350 in it, but was running a single electric pull fan with no shroud. That setup kept the temp at a constant 180F all day every day even in bumper to bumper traffic.