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Discussion Starter · #1 ·
Hi All,

First time here.

I own a beautiful rosso 1994 155 V6 which I love.

I have owned it for a year. Up until recently my home to work commute was only about 4km. Once in the morning, once at night. Now it is about 10km. So it doesnt get driven for long periods of time.

Now my problem.

Last week I drove for about 50 minutes in rush hour traffic for an appointment. I did not notice any warning signals on the water temperature gauge. After my appointment I drove back and after about 10 minutes I noticed the temperature light and saw that the temp was about 120c. I immediately started to look for a garage and parked.

Steam was coming out of the main water tank area. After it cooled down it took alot of water to fill it.

I took it back to my mechanic who thought that he may have left the cap off. He replaced the water and coolant and I thought that was the end of my problem.

Yesterday, It happened again, but I was watching for it. After about 50 minutes of driving, it started to overheat [110deg]. I pulled over and let it cool down. This time it took less than a litre of water.

Becasue I normally dont drive long distances, I might not have noticed this problem. However, it cant have been going on for too long.

My mechanic has done a compression test on the head and it seems fine - which seems to rule out a cracked head. After reading a few threads on here, it might be a blocked or corroded radiator, or the mechanic has also mentioned a blown gasket.

Anyone got an idea on what it could be? Any common causes associated with this problem?

The oil temperature seems fine, but the pressure guage is always low - particularly after being run for a while - I saw another thread about this [not terribly worried about that].

I appreciate your help.
 

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I had something similar happen to me 2 years ago. It was "simply" the engine fan not kicking in, :eek: but...

That was due to electrical problems on the fuse panel, which in turn kept melting the fan's electrical plug.

Later on, I did have another engine heating problem, and the radiator was indeed corroded and leaking. The mechanic used a sort of compressor which goes on the coolant tank, and right away the leak appeared very clearly on the rad.

Hope this helps.
 

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The first thing is to check that the radiator fan is working.

It should come on at 92C and then stay on until the engine cools down to 90C.

If the fan doesn't work then that's the problem. Any car will heat up in traffic etc, only you never notice it because the fan cuts in and cools it down continually.

If the fan doesn't come on, it could be shagged or it could not be being "told" to kick in..

The temperature gauge you see in the car reads the temperature off the engine block (those wires connected to the thimble shaped protruberance next to the thermostat) whereas the fan only comes on if the water in the radiator hits 92C.

The temperature sender/switch in the rad' is the big brass nut thing on the back/right of the rad' (as you look at it) with 2 wires going to it. When the temp. hits 92C it closes a connection and the fan comes on. It doesn't do anything you can see inside the car.

So, is this sender working? If you unplug the connector you can bridge the connection with a piece of insulated wire. That replicates the effect of the sender when the temp. reaches 92C. With the ignition on, the fan should come on regardless of the temp. of the water in the rad.

If it doesn't come on, the sender could be faulty or the feed to it may be broken. Check the feed (dunno if a simple voltmeter will do it) but the sender is a replace only job.

If the feed is okay and the fan still doesn't work, the fan could be knacked (or leccy to it may be duff). This is much less likely than the sender being defective (age and being immersed in water all its life).

If all that checks out, make sure there is no air in the rad, as if it fills the rad enough, then coolant won't be able to get in to the height of the sender. The sender will think the "coolant" (actually air) is less than 92C and never trip the fan. You have a bleed screw on the reverse/left of the rad' near the top. Just unscrew it slowly till coolant seeps out and that's the rad' bled.

Ralf S.
 

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.

The oil temperature seems fine, but the pressure guage is always low - particularly after being run for a while
The oil pressure gauge sender is the thing that looks like an egg cup underneath the raditator top hose, next to the coil pack. It has a single wire going to it in a yellow (?) plastic sleeve and a rubber cap.

These do stop working very well eventually but it's nothing to worry about. You can put a new one in easily (just unscrew it and replace) and it does look good when the gauge comes back to life.. :) Sender is about £40 though.. so it's an expensive indulgence.


Ralf S.
 

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Discussion Starter · #5 ·
Thanks Ralf and Pierre.
I will check the fan, then the radiator. All good advice - and hopefully not as big a problem as I thought. Repairing these things in NZ can be costly.

Cheers
 
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