Thread: 3.9 V8 ran hot yesterday....what now?

Hey All
Bit of a long story
During a quick squirt out in talarook forest yesterday the old girl got pretty hot. I think it's had a slow leak somewhere and has only been getting water top ups.
I had driven about 80 ks to my sister's in tallarook chilled out for a bit then went out. I checked the oil and water at my sister's before leaving and noticed water around the filler cap. Didn't think to much of it because it still had water.
So we headed out to hit the tracks and it was a fairly long steep uphill run to get there about 20 mins or so. Got to the dirt and found a track it was all a slow climb in low, had no dramas. Next track was steeper and longer a fair bit of work on the old girl. Then out of nowere the temp gauge moved ever so slightly, I'd never seen it rise above the little waves on the gauge. Now I know the gauges are fairly usless so I stopped at a flat and noticed a tiny bit of steam, popped the hood and it was coming from the expansion cap only. Still had plenty of water though, so I let it rest for a few mins. Then we pushed on and the track just got steeper and rockier, pretty difficult with my current setup no lift and that wheels scrubbing. Temp gauge rose up more so I kept on stopping when I could, in the end it got up near the top line but i didn't let it sit there. It never went above in the H area. We had to turn around because the track was getting brutal and I was getting hot. I managed to get down fairly quickly I had too get back to the road stopped once or twice on the way down.
Got to the road still no steam from the engine only the expansion tank. I let it cool for a few minutes and put another 4ltrs in it. I'm hoping it's just steamed out of the expansion tank (high hopes) and not leaked into the block. Engine sounded a bit touch and go for a second but it come good ran fine nice and smooth.
Drive back to my sister's all downhill awsome had no problems at all the disco ran like she should. Got back to hers no steam, topped up the water and left the car on with the heater running no dramas. Drove home 80ks cruising along at 100-110 no dramas. It's an auto and the trans warning light never came on either.
So where do I go now?
I didn't see any water on the ground, oil in the water or milk under the cap.
Is it worth putting a chemi weld product in or is it a no go with these engines?
The waters gone somwere but could it have just evaporated out of the expansion tank because it was just water?
Do the Welsh plugs need changing regularly?
I'm using full sin oil by mistake could it be heating quicker?
Do I just flush and fill with coolant get an aftermarket gauge and hope for the best?
I don't know where I should start looking with these engines summers coming I don't wanna get stranded because she's cooked on me.
Thanks for reading
Cheers Jim

Originally Posted by LRJim

That's what I was thinking it spins but I dunno if it engages when hot. What about installing an electric fan?

I put electric fans on the stage 1. I had more overheating issues with those. Viscous fan works fine.