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Parked my truck at the store yesterday after a short drive and had steam coming up around the hood And noticed the temp gauge was almost in the red and it was leaking. Topped up the radiotor res let it cool down a bit and drove it home very gently. i saw there was coolant leaking down my trans and drive shaft the steam was coming from the rear of the engine inbetween the firewall and the engine so damn tight back there its hard to see what exactly the problem was.. Waited a few hours to cool completly and filled the rad took about a litre maybe a bit more. Started it up again and the hissing and overheating began imidiatly. Within about 2 mins it started making a constant whining noise like a bearing or belt and i was in the red again.. I saw some posts on here about possibly being a heater core hose. Wondering if someone with more knowlege can shed some light on this for me.
I should add its always leaked coolant from back there somewhere but never this much and ive never had it overheat except once after climbing a 2km mountain a bit fast.
Thanks Alex
Last edited by Yodes; 08-13-2017 at 05:45 PM.
Reason: forgot something
Back of the motor/firewall area, it's probably the water by-pass hose. U-shaped to the right in pic.
Not particularly a fun one to do if you have big hands.
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Thanks for fast reply the pic helped alot i got the hose off n its badly cracked on the first time probly where the slow leak was the whole time iive had the truck. N ya my hands are big and it was a pain. Had to remove an upper hose
To anyone else with this problem id recomend using channel lock plyers to hold the hose clamps and a trim removal pry bar or something similar to help pull the clamp off at the same time since it was impossible for me to pull the clamp right off the connection. Thats what worked for me.
I tryed taking a pic of the tool and old hose wudnt let me post ill try later. Ill get er all patched back up tomorrow and let u know the result. Hopefully the squelling gos away to
Well no more leaking after the new hose was fitted nut still reading in the red for heat.. Im hoping changing the thermostat will help ill try tomorrow. I was thinking it was a faulse read cause it got hot so fast and the engine was hardly warm to the touch when the temp gauge was almost in the red but i suppose it measures the water temp not the block
I doubt the thermostat is the problem. It sounds like you have been leaking coolant for a long time, and it eventually caught up with you. I'm guessing you have an exhaust-coolant leak.
In the short run, you could try to check the coolant for exhaust products with a chemical tester like this:
@#$! What makes you think I have such a leak can you elaborate please? It has been slowly leaking a long time now. No more than a cup or so every 2 weeks hardly anything. You think my head gasket is gone?
The new water bypass hose has sealed the leak no more hissing or screaching just overheating
These engines have a really bad habit of blowing the head gaskets any time they get hot. especially #6 due to the combined exhaust manifold, all that heat on one cylinder. Headers or a block off kit. I would suggest if you go that route drop everything and pull the engine forward a couple of inches to get some working room, its damn tight back there.
Park it uphill to get bubbles out.
Could be you are fine too.
Hope its not a head gasket jesus.. Ill start looking for a 3.4 motor to do a swap if thats the case.. I hate this engine.
So even though im not leaking coolant anymore, just that its getting hot still you think it could be the gasket? I was thinking if my thermostat was hooped the water in the block not being able to het to the rad, would heat until it found a way out (my cracked bypass hose) then when i replaced the hose it would still heat up until the thermostat is replaced. No?
Thermostats don't cost much, so sure, go ahead and replace it. You could even test the old one after it's out.
But overheating any engine is just not good for it. You've got a temp gauge, but oh so often they only tell you anything when it's already too late. You weren't overheating before, then it went really hot, and now it's staying hot. Sure, a failed-closed thermostat could cause that (your leaking won't remove enough heat to make any difference, so your only hope is that the thermostat is the cause of it getting hot.)
A 3.4 swap is no small undertaking, but those who've done it seem to like it. It's a lot more work (so far as I can tell) than replacing a head gasket.
Getting conflicting answers on where the t-stat is some people are saying the upper radiator gos to it some are saying its the lower hose. Book says upper hose but the picture of the housing looks like the lower hose fitting...
... some people are saying the upper radiator gos to it some are saying its the lower hose. Book says upper hose ...
"some" people? "Book"? What book are you looking at?
The service manual shows the thermostat housing bolted to the water pump, which is at the bottom of the engine (so the output goes to the lower radiator hose). http://web.archive.org/web/201311071...10thermost.pdf
Different forums people where saying to follow the top hose from the radiator and my haynes manual also said top hose.. Anyway i went with my gut and did the bottom hose. Got the new tstat in and bubbles out of the rad. Drove to work today and no overheating i think im in the clear.
The new tstat was a bit different than the old, it had a 1/8 inch hole through it with a strange brass plug thing, the old one did not have this.
Ill order a genuine one and swap it should be ok for now though. Thanks everyone for the help
Ah i see, is it ok to have that kind of thermostat instead of stock without the jiggle valve? And yes i remember i did put it facing up thinking it would work better that way lol fluke..
Is that just a new saftey feature to help hot water escape to your rad or something?
Thanks again for the help everyone great site. Next time ill ask about my pesky vacume system that may have played a role in this
About to go on a 7 day 4x4 and kyaking trip so hope this holds up.
08-13-2017, 05:41 PM
1991 3.0 hissing coolant leak overheating bad
i got the hose off n its badly cracked on the first time probly where the slow leak was the whole time iive had the truck. N ya my hands are big and it was a pain. Had to remove an upper hose
