mad_pete Posted September 10, 2009 Author Share Posted September 10, 2009 okay so it is overheating. :-). So what's next least expensive thing on the list of things that cause overheating ? I've done stat rad cap heater matrix Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 10, 2009 Share Posted September 10, 2009 Water pump? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 10, 2009 Share Posted September 10, 2009 In simple terms it could be Too smaller rad Not enough coolant Mismatch Pulley to Water pump Poor air flow Impeller issue Thermostat to high rating blocked / part blocked rad causing flow issue Not pressuring enough or dreaded liner / block issue Combo of the above Personally start with fitting a lower stat from memory 70 something that will drop the temp and what ratio of antifreeze are you running ? Can you take some pics of Front of truck rad / fan(s) cowling Header tank type and plumbing of system Nige Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 10, 2009 Author Share Posted September 10, 2009 The ratio of anti freeze has been normal, low and high I'm not sure I've noticed a difference with different mixtures. The engine came from a 90 with a na diesel rad and that didn't overheat without a cowl. The engine has the 12 blade viscous fan that came on the 4.2. The cowl is a close fit as I had to slightly trim the blades and cowl to stop if rubbing. The fan is a snug fit to the hole. These pictures are from my just what I had to hand so if you need any close ups let me know The header tank is the 3.5 one and a bit small. My winch safety valve stops me mounting the rangie one. It has a pipe brazed to the bottom to feed the bottom hose and a t piece plumbed into the smaller top hose from the original feed. Apart from the header tank the plumbing is the same as the other 90 the engine came from The front is basically the same as the picture except the spot lights are now slightly bigger ( and yes I could take them off as they are a whacking great block on the air but I would have thought the system would have enough slack to handle steady driving) I think to start with the spots weren't on and I still had a problem although I didn't have the cowl at that point. Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 11, 2009 Author Share Posted September 11, 2009 Okay I checked a squirt log file. The engine on idle will warm to 90. Running is at 95 and a good prod on the throttle is followed about 4 - 6 seconds later with a temp spike to 103. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 11, 2009 Share Posted September 11, 2009 Humour Me Chnmage the Thermostat for the lowest 70 something one remove lights from the front re do and report back I think its just a cooling issue and that the amount of air flow / clear air route in / capacity etc it just not quite there the above may suprise you Nige Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 11, 2009 Author Share Posted September 11, 2009 THanks. How good would that be if it's just a cooling issue. Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 11, 2009 Author Share Posted September 11, 2009 Hmm how marginally annoying to say the least, a second exhaust gasses in coolant test ( I had one done when this started ) has come back positive. Off with it's heads time. Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 11, 2009 Author Share Posted September 11, 2009 or is it ? Should I just bin the engine and spin the wheel of luck on another V8 from somewhere ? ( I have to get one that works sooner or later surely ) Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 11, 2009 Share Posted September 11, 2009 Ah Ha ! Right if you have a positrive test then heads off time It could just be a head gasket - if your lucky Take pics when off and post up for diagnosis, all pistons from top in their banks Reverse side of both heads Head gaskets themselves 1 bit down... 1 to go Nige Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 13, 2009 Share Posted September 13, 2009 Probably irrellevant now ive seen that last post but i'll say it anyway Changing the stat for a 70deg one wouldnt fix anything unless the stat itself was broken. If the radiator (or some other part of the system) cant keep the engine cool with the stat open (which it must be if its at 95-103) then fitting a lower temperature stat wont change anything, it might take longer to get up to temperature, but the radiator would still be insufficient and it would still overheat. I'm just hoping my Disco is ok... Finally got the new dizzy on and got it running again, now i need to move it 200 miles from livingston in scotland to cleveleys in lancashire. Its only really been run round and about livingston on short trips and seems to have a bit of a thirst for coolant. Every time its been run bar the last time its used some coolant... Last time out it didnt actually use any though, wasnt driven for long, maybe 5 miles, but it used water on shorter trips before, so fingers crossed I'm kinda hoping its just been small airlocks working themselves out of the system, but that seems a bit too good to be true for my luck! Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 13, 2009 Share Posted September 13, 2009 Er No A lower temp sat will make an engine run lower in its heat ranges If the rad is too small, or there is an issue with the build etc then a lower stat can help, but true its better to fix the problem However 105 is not "that Hot" my advice re fitting a lower stat is to see if it then drops the internal latent heat, by the lower stat dropping the temps If it does then its a design / mix of parts issue, if it stays the same then leans more to Liner / bliock, or maybe blocked rad Differing thermostats drop / alter running temps - period Nige Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 13, 2009 Share Posted September 13, 2009 The stat simply controls the flow of water thru the radiator. If, with the stat fully open, the engine overheats, then regardless of the stats rating the engine will overheat. It might take longer to heatsoak, but if the engines running at 95c during normal driving, then regardless of it being a 70c or 80c stat its still (eventually) going to reach 95c, as both stats are wide open well below the 95c its levelling off at. Even with no stat fitted whatsoever, it would still get to 95c, eventually. Imagine a extreme example, you take your radiator and cover 90% of its surface area with cardboard. Drive it around and the coolant levels off at 110c because the 10% of the rad that does have air flowing thru it is unable to dissapate enough heat to cool the engine any further. If you then remove the thermostat and drive it round, you've still only got the same 10% of rad to dissapate heat which is still massively insufficient. The fact the thermostat isnt there makes no difference, it would still level off at 110c. If your cooling system was working properly, and the rad has plenty of spare capacity, then yes fitting a lower temperature stat will lower the running temp, but if the cooling system isnt able to dissapate enough heat to cool the engine for some reason, changing the stat isnt going to make a difference. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 13, 2009 Share Posted September 13, 2009 So How come when you know everything about everything you can't even get a V8 distibutor in on your own ? A lower thermostat drops the operating range of the Engine, No, it won't cure a cooling issue, but can help control it, which is why many race cars with V8s 'fine tune' cooling systems via thermostats.. ...but then again you know everything about everything it seems, ...so I'm wasting my breath Nige Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 14, 2009 Share Posted September 14, 2009 Lol, i dont claim to know everything about everything, which is exactly why i was asking about the distributor, this however is just general principles. Theres no need to get narky about it! If you disagree with my point, then explain whats wrong with the points i've made... If the radiator and cooling system is upto the job, then what your saying is correct. If however its not upto the job, either because the rad is blocked or the pumps knackered or whatever, all you'll do is mask the issue for slightly longer, if at all. If the radiator and cooling system was infinitely large, then the temperature of the engine would sit at the stats control temperature. As it happens thats not the case, and the radiator is sized so its large enough to handle the (standard) engine working under full load for prolonged periods. This means that for the most part, it will be able to keep the coolant temperature within a few degrees of the stat temperature under most operating conditions. What your saying is fine, to a point, but if the engines overheating because the rads choked with mud, or the pump impeller has sheared, or the head gasket has gone etc, fitting a lower rated (or no) stat isnt going to change anything. If you think of it in terms of energy dissapation, the temperature climbing means your dissapating less energy than your generating, so regardless if you start at 70c or 80c the temperature will still climb at the same rate. Ok it might mean you can run the engine at full load for 2 minutes instead of 1 minute before overheating, but the engine should be able to run at full load constantly without overheating. Quote Link to comment Share on other sites More sharing options...
adam300Tdi90 Posted September 14, 2009 Share Posted September 14, 2009 OT alert... Oooooooooooooo!! Quote Link to comment Share on other sites More sharing options...
mad_pete Posted September 17, 2009 Author Share Posted September 17, 2009 Right heads are off. Everything looks fine except slight black mark between cylinder 8 and the rear water channel. no steam cleaned cylinders. Some head bolts were a little lose and water pump has some play. Where is the best place to get some nice composite gaskets from ? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 17, 2009 Share Posted September 17, 2009 Real steel - composite gaskets, rubber rocker cover gaskets. Quote Link to comment Share on other sites More sharing options...
mad_pete Posted October 2, 2009 Author Share Posted October 2, 2009 Nice, new gaskets on and all the water where it should be and top holding nicely at 90. So looks like it was the head gasket and corroded injector plugs. Thanks for everybody's input Running rich now it's back on 8 cylinders which is nice for power but doing about £1 a mile in fuel ( ouch ). I pulled the fuel cap off and there was a suck in of air, that's a blocked breather isn't and reduces mpg even lower ? Quote Link to comment Share on other sites More sharing options...
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