Well I have just finished replacing that extremely hard to get at hose that is situated under the manifold.
My earlier post was asking for advice on how to accomplish the task and since no step by step advice was given I thought I would write up my procedure for anyone else considering the task.
As mentioned earlier my vehicle is a petrol model and and the heater hose at the rear of the engine and under the manifold is in such a difficult position to get at that I wanted to replace it as preventative maintenance. The hose and clamps are the originals.
You will need 10 & 12 mm spanners, screwdriver but most importantly pliers or similar but no longer than 5 inches. I used a 5" pair of vice grips. These small pliers are needed to remove the original spring clamp securing the hose to the engine.
After draining the coolant remove the heater valve complete with all hoses. The easiest way to remove the hose from the firewall to the heater valve is to cut it off.
There is a right angle hose from the heater valve assy that goes to a steel pipe which in turn goes down to hose below the manifold. Undo this steel pipe which is bolted in 2
places towads top and btm, you won't be able to remove it at this stage because the btm hose is still holding it.
Where you have to get your hand in to get at the btm hose there is a large wiring loom which is secured by a clip. Unclip this loom and push it down a little, just an inch makes a big difference. There is also an earth strap on the manifold nearby which can also be undone.
Now it is still very arkward to to get at but the best thing is to cut the btm hose in half allowing you to remove the pipe. When the pipe is out of the way
use your pliers to expand and remove the spring clip. This took me about half an hour, I just couldn't get anything onto the clamp. Of course I was committed at this stage because I had cut the hose and anyway I wanted that hose relaced!!! All of a sudden the vice grips took hold and the clamp was off.
Now continue cutting until you have remoed the remainder of the hose. Be careful not to damage the spigot when cutting the hose off. Now it is an easy job to replace all the hoses on the heater valve and pipe. With only the btm hose on the pipe slide the hose onto the engine spigot and still use the Toyota spring clip but position it towards the front for ease of access. Bolt the pipe back into place.
The same with the heater valve, after all the hoses have been reassembled slide the hose onto the spigot at the firewall, positioing the spring clip for easy access.
Refit the valve cable, wiring loom clip, earth strap and fill with coolant.
I should point out that these original hoses were still in excellent condition after 14 years in service. I was told by people at Toyota that these original Toyota hoses would last for over 10 years provided that the coolant was replaced regularly ( every 2 years I do it)
I hope this info can be of benefit to anyone else contemplating heater hose replacement.
Best regards Cruiser.