Chev 6.5L Diesel Engine Tips and Tricks

[Mike Amen]

Hi.
Does anyone know where I can download an engine manual for my chev v8 diesel? It's in an 80 series so I only need the engine section, as all the rest of the car is still genuine Toyota.

Thanks

Mike.

[Boxa]

Mike,

I have been looking like crazy on the net. Everything keeps pointing me to the Haynes Chev service manual which covers the whole chev range petrol and diesel so nothing specifically for the donk we have. That retails for about $40.

Keeping my eyes pinned....

[crewser]

have you had a look at www.thedieselpage.com/ theres a bit of info there on 6.2L & 6.5L diesels. I have a print out of a manual for the 5.7L & 6.2L but cant find a publishers name on it. you could try lindsey down at linquip www.linquip.com.au (07) 54867900 0412 611 602 he`s normaly helpfull

[kingchevy]

Whats wrong with it?

[Tomax]

I've got one here from when we had a 6.5 Chev powered GQ in the family. It is one of the Haynes Techbook series (Haynes Automotive Repair Manual Series) - title 'Diesel Engine Repair Manual' No 10330 (17336) and covers GM (5.7,6.2 and 6.5 litres) and Ford (6.9, and 7.3 litre) engines. Published by the Haynes Publishing Group in England, and Haynes North America, Inc in the USA. ISBN 1 56392 188 X
Any good technical bookshop should be able to point you in the right direction.

[1tuf75]

Im pretty sure the holden suburbans come out with the same 6.5 chev v8may be worth a look for one of those if all else fails

[Les Addison]

The manual you are after is often on Ebay , they are ex US army in book form, about $15usd . They are very comprehensive. I have the 6.2 manual . The engines are almost identical, all parts inter fit with the exception of the rear main oil seal ,and early model 6.2 head gaskets. I have spent 10 years repearing ,rebuilding and fitting these engines to various vehicles, any questions regarding this fine GM product, I would be happy to answer on the forum or by email . Les ----- Brisbane

[kingchevy]

Les why does my 02 6.5 overheat in the 75 series cruiser ute?? it seems to hold the heat and build up over long drive periods? or if you let it sit an idle within 5 mins its boiling?

[Les Addison]

Hi to Kingchevy . wow man, you have touched on one of the favorite chevy questions. I chased the problem for 8 years,for my own, and several other clients . For all overheating problems there is rarely one answer alone, to establish the cause . Firstly on these engines there is 2 types of belt drives, the early 6.2s and 6.5s had V belts , the later ones had Serpentine belts. If your engine had a serpentine belt ,and you now have fitted V belts, the waterpump will be rotating in the wrong direction. Now you'r going to ask me how do I tell . When I work out how to add pics, I will post them . Ok next thing .You have to start with the basics . Does the fan lock up PROPERLY ,can you hear it roaring , does the thermostat work properly and what type is it & what temp is it.(( Are you positive the gauge is accurate.)) Is there a coil spring in the bottom hose. Air flow into radiator.Is there any restrictors in the system. What width belts. How many belts drive it. What kind of fan are you using,(do not use electric fans). What kind of pulleys are on it . Who did your conversion ?? and engine build. Now we get to the good part.. What type of radiator is it . Std Toyota ? alum or copper.Or one of these so called you beut ones. What side, pass, or driver, does the top rad hose go into. Run the motor till it gets to normal temp, take the top off the overflow bottle, put the rubber tube into a half full coke bottle of water, raise the revs to about 1500 and check to see if there is any bubbles blowing from the tube , which would indicate a blown head gasket.... From now on it gets interesting. Let me know all the answers to the questions, before we get to the nitty gritty.. There is an answerI will tell you when all else fails...... Les

[Mike Amen]

Originally Posted by Les Addison

The manual you are after is often on Ebay , they are ex US army in book form, about $15usd . They are very comprehensive. I have the 6.2 manual . The engines are almost identical, all parts inter fit with the exception of the rear main oil seal ,and early model 6.2 head gaskets. I have spent 10 years repearing ,rebuilding and fitting these engines to various vehicles, any questions regarding this fine GM product, I would be happy to answer on the forum or by email . Les ----- Brisbane

Thanks Les I'll look on eBay.

Can you tell me where the Tacho getis it signal from on the 6.5L? Mine seems to stick when I first start the motor. I know it's not the head unit, because if I tap it the needle jumps. After the motor is running for a few minutes the tacho will then start working properly. BTW it's in an 1994 80 Series.
Ta
Mike.

[Les Addison]

Hi Mike, it can be sent from 4 places ,1- the oil pump drive at rear of the engine in the middle of the V. 2 Ring gear teeth from a magnetic sensor in bell housing . 3 from an after market kit with a sensor mounted on the timing cover aimed at a pin placed in the harmonic balancer. 4 6.5s Had a sensor with 2 wires that fit ito a hole in the left side near the bottom of the timing cover..

[Les Addison]

Mike , there is one or two on Ebay, look under (chevy diesel) world wide search. Les

[Mike Amen]

Originally Posted by Les Addison

Mike , there is one or two on Ebay, look under (chevy diesel) world wide search. Les

Thanks Les
I've bought it. It comes as an electronic copy on CD, with downloadable updates.

Mike

[Les Addison]

Good stuff Mike . Some of the engineering shops in USA do some remarkable things with these engines. You will never run out of parts for them , as AMG Hummer bought the entire machinery from GM and now fully produce the engines, with some very good modifications to their known problems . Les

[Les Addison]

This is to identify the two different types of water pumps fitted to V8 Chev diesels
The left one is for Vbelt drives , the right one is for Sepentine belt drives .Note the difference of the top section of the pumps . It can easily be seen on your engine, just below the oil filler tube where it goes into the engine.. Serpentine pumps run in anticlockwise direction,as the belt drives the pump from the outside of the belt. Note -- Dealers will be aware of this on their instalations, People who purchase their engines else where , may not be aware of the need to change the pumps, if fitting V belt pulleys..Les

[kingchevy]

Originally Posted by Les Addison

Hi to Kingchevy . wow man, you have touched on one of the favorite chevy questions. I chased the problem for 8 years,for my own, and several other clients . For all overheating problems there is rarely one answer alone, to establish the cause . Firstly on these engines there is 2 types of belt drives, the early 6.2s and 6.5s had V belts , the later ones had Serpentine belts. If your engine had a serpentine belt ,and you now have fitted V belts, the waterpump will be rotating in the wrong direction. Now you'r going to ask me how do I tell . When I work out how to add pics, I will post them . Ok next thing .You have to start with the basics . Does the fan lock up PROPERLY ,can you hear it roaring , does the thermostat work properly and what type is it & what temp is it.(( Are you positive the gauge is accurate.)) Is there a coil spring in the bottom hose. Air flow into radiator.Is there any restrictors in the system. What width belts. How many belts drive it. What kind of fan are you using,(do not use electric fans). What kind of pulleys are on it . Who did your conversion ?? and engine build. Now we get to the good part.. What type of radiator is it . Std Toyota ? alum or copper.Or one of these so called you beut ones. What side, pass, or driver, does the top rad hose go into. Run the motor till it gets to normal temp, take the top off the overflow bottle, put the rubber tube into a half full coke bottle of water, raise the revs to about 1500 and check to see if there is any bubbles blowing from the tube , which would indicate a blown head gasket.... From now on it gets interesting. Let me know all the answers to the questions, before we get to the nitty gritty.. There is an answerI will tell you when all else fails...... Les

Woohoo finaly someone who knows what there talking about allright my engine was done by brunswick diesel. It has a solid fan (I had a viscous clutch but ditched that to see if it helped) it has an upgraded radiator cost me 700 from brunswick I dont know the species but its not aluminium it has the twin thermostats with one removed.(this didnt help either way just took longer to get to running temp). the motor is a 2002 with the oil injectors and ceramic pistons for the turbo altough I dont have one. I'll have to check on the hose but I am fairly sure its not a cavitation problem in the hose because if you let it idle for 15mins it slowly gets hot as well as when you're driving it. The best way to explain it would be to call it heat soaking once the motor gets over running tempature it seems to hold the heat in the motor and slowly climb but if you back of under say 80-100 it goes back down. (I know you're going to say but you're driving to fast but when you're driving out to cairns 800kms of dirt can get very taxing if you sit on 80). allright thats all for now

[Les Addison]

Brunswick diesel, do a fine job on their installations & know the problem well . I know Greg and I now know how you rig is set up. One of the known problems with these engines is the waterflow around the block and cylinder heads. In the full sized GM vehicles the radiarors are aluminium that hold about 30 Lt of coolant and they have enormous fans. But allas, they still get hot.. They have got after market Hi flow water pumps for clockwise and anti clockwise engines , they put out about double the flow and pressure. As far as I know , no one has imported these into OZ(yet). Ok -- The twin thermo's is a help with std water pumps ,as it effectively doubles the volume that is pased to the radiator . As volume is a product of pressure , these pumps are not quite good enough, (more on that later).. The volume of water in a 75 is 17Lt dry fill. So you can see it is struggeling to start with.. Your radiator is the best one available (reserched and developed by Brunswick Diesel) the part # is Nat Rad Toy 9488. This core can be fitted to Nissan cross flow, and other models of Toyota .It has 3 rows, the cores are 16m long & 2m wide there are 4 cores per lnch and 14 fins per inch. This radiator passes 15 -20% more than others, with less wall friction . One of the things often neglected is the Cap . Toyotas use 13lb (Fit 15 lb ). Also quite often there are small particles that flow around the system, they get lodged under the return valve seat , which causes the water to exit into the recovery bottle, and actually overflows it. What happens then is during cool down, it sucks the water back in the radiator , but as it has been lost it does'nt re fill it up . (Check it often) If there is a lot of crap in there, Disconnect the heater hose and fit an inline water strainer (ordinary garden type) and re plumb it back into the water crossover , The other end to the suction side of the pump , there are 2 fittings on the pump ,one is the bypass hose , use the other one. Check it and clean it till no more particles collect on the gauze.. As in most engines there are hot spots. The easy ones to get to in these engines ,are at the rear of the two cylinder heads , some times one is used to go to the heater , the other one is usually left blank . Remove them and install suitable fittings, (might have to drill and tap to take 1/4" hose barbs). Best place to put the hoses ,is into the top rad tank , but they can go back into the water cross over . What happens ,it causes a water flow from the hottest part of the engine , the water actually boils to superheated steam , causing minute air bubbles which find their way to the water pump. As Gm water pumps are a left over from Barny Rubble's Chevrolet. They then don't circulate any more, and the hotter it becomes the more they cavitate.. Will start another Post . I can add pics if any one is interested.. Les

[Les Addison]

Test the thermostat , make sure it starts to open before boiling point, and at boiling point it should be open approx 6to 10 ml . The thermostat should have about a 38 ml opening. Smaller ones will restrict the flow. Best ones are the genuine Chev , or the Toyota 1HZ with the foot valve cut off.. Next thing to do is install a low, 0 to about 50 lb pressure gauge into the water system,( before the thermostat) .Run the hose into the cabin& velcro the gauge to the dash top , On a Cold engine with the thermostat closed, the pump should put out about 20 to 30 psi at 2500 to 3000 rpm . Drive the vehicle and note that when the thermostat opens it will drop the pressure. At normal opperating temp it will drop back to about 12 to 14 . When the engine gets to over hot it will drop back to zero and may even fluctuate. This will indicate there is no flow through the system.. Ok , As this is not the only thing that can cause overheating . The air system is next to check, obviously the amount of junk you have in front of the radiator will inhibit the flow to some extent. The main thing is the fan and the cowling. Nissan fans are not the best, Toyota is better, V8 Comodore or Statesman 7 blade metal fans are better again, and the one I am using seems to shift more air than most is the 10 bladed FalconEA to ED with the heavy duty viscous coupling, seems to work well. It has a left hand thread , so an adaptor has to be made to fit the bolt pattern..allow aprox 1/3rd to 1/2 of the blades to be outside and preferably in a tunnel. Ihave installed a make shift scoop under the bull bar ,to see if it makes a difference. It works so well it has even reduced the amount times the fan clutch locks up. (See how to test the viscous coupling on a previous post)..After my brain cools down a bit I will post some more info on Modified water pumps..Les

[Les Addison]

As most of us mechanics over the years have heard , put a restrictor in the system , this will slow the flow down so as to keep the water in the radiator longer , this a complete fallicy, the problem is to move more water through, while keeping the block full, under pressure to eliminate any air pockets. While we are on water problems , you can make a test on your pumps performance . Make up a clear pvc top hose, run the engine till it gets up to normal opperating temp, and higher if possible. If the sysem is faulty ,you can see the small bubbles through the pvc if you shine a light through the back of the hose. Note don't drive the vehicle as the hose will swell and come off.A glass bottle with the end cut out is better ,and can be driven.. Test for blown head gasket as in previous post.
OK... Now it gets technical. One of the most agrivating of all things especially in diesels, this one in paticular is that most of them are over fueled, this V8 has no brains, they will just keep on pulling, regardles of hills or load. When you have your foot down ,it feeds unnecessary fuel into the cylinders ,which equates into heat. The only way to check this is with a Pyrometer(all diesels should have these instead of useless tachos) . They are not expensive, about $260-$280 from Pyro sales Bris. They are small rectangular Digital read out ,you can velcro to your steering column. Probe fits into the engine pipe. The max exhaust temp for the V8s is 650C. I have found if it goes to 550C relitively easy up most hills, and wants to go higher,( easily),it is over fueled . Another indication is if you have to back off to keep it under 550 ..Rule of thumb You should be able to drive it up and over most hills without backing off. (Too much), and of course as I said they have no brains , so change down a gear and watch the EGTemp goes down, the revs go up, pressure goes up , fan goes faster. I went to the trouble of having my water pump re engineered , in Melbourne, by John Bennett at Ecotrans PTY LTD . He did an exelent job , it pumps about 75% as much more volume and pressure than the orriginal one . Went to WA , overheated all the way. Got to Brunswick , had a yarn to Greg. Threatened him with death, or worse, if the new radiator didn't fix the problem. Put my viscous fan back on, Has not overheated since. Hope this has helped diagnose the faults. Les

[Les Addison]

Right bank 1/2''hose from T piece to water crossover. Murphy gauge temp sender in top of T to allow water flow to indicate correct water temp.. Left bank 1/2'' hose to water crossover . A single crossover hose with a T piece in the middle can be used, then only one hose needs to be plumbed into the crossover. Further testing has proven if the bleeders are plumbed into the crossover instead of the radiator the engine warm up period is much quicker especially in colder climate and by using 1/2'' hose allows much improved overall temperature control by the bypass system.