roadsubiedog Posted October 20, 2015 Share Posted October 20, 2015 1984gl. Motor runs great but after 10 minutes slowly, i mean very slowly starts to overheat. Been reading every thread here on EA81 head gasket issues and someone suggested it may be intake manifold gasket failure? how to tell the diff between this and head gaskets? do you do a compression check first? if i do have to do the head gaskets are the intake manifold gaskets automatically replaced as well? my main question would be how to pinpoint problem ? already have replaced water pump, t-stat, flushed radiator. everything easy. i posted story last year that my son got the oil changed and they did not put oil back in and he fortunately stopped after a few minutes when he noticed a problem. not sure if major damage was done. we started it and ran it 5-10 minutes about 10 times and it runs nice and smooth and makes no noises and always shut it off after it started creeping up past normal point. oh, ya. oil has been changed twice and is very clean. no milk or water. would it be simple just to change the intake gaskets or does this story suggest obvious head gasket failure? Quote Link to comment Share on other sites More sharing options...
kgrove56 Posted October 21, 2015 Share Posted October 21, 2015 I would think you should pressure test the radiator if you have a bad radiator cap the water will boil and leak out the cap at a lower temp causing you to lose water Quote Link to comment Share on other sites More sharing options...
kgrove56 Posted October 21, 2015 Share Posted October 21, 2015 I would think you should pressure test the radiator if you have a bad radiator cap the water will boil and leak out the cap at a lower temp causing you to lose water Quote Link to comment Share on other sites More sharing options...
kgrove56 Posted October 21, 2015 Share Posted October 21, 2015 The fan kicking on? Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 21, 2015 Author Share Posted October 21, 2015 this problem started immediately after son overheated it with no oil in motor. yeas, i believe the fan kicks on. the temp does go down when you put the heater on full but eventually starts overheating anyway. just takes a little longer. Quote Link to comment Share on other sites More sharing options...
NV Zeno Posted October 21, 2015 Share Posted October 21, 2015 (edited) EA81 engines are pretty bulletproof. Rarely have I seen gasket failures in them. Did you use a Genuine Subaru thermostat? These engines seem to be very sensitive to that. They don't like aftermarket t-stats, so it's Subaru only. You mentioned the temp gauge creeping up past normal. Did you shut down before it reached the top? Perhaps with all the "stuff" you've done so far, there is a new "normal" that's a bit higher than before. If there's no leaking and there's no milky oil, gasket failure just doesn't make sense. Just throwing stuff out there. Please let us know if/when this is resolved. Hey just noticed your profile sez Tahoe..Are you still here? Edited October 21, 2015 by NV Zeno Quote Link to comment Share on other sites More sharing options...
DaveT Posted October 21, 2015 Share Posted October 21, 2015 Intake gasket failure won't cause overheat. Unless you run it long enough to loose too much coolant. My experience has been overheat and you will need to replace headgaskets. Sooner or later, but it is inevitable. Running without oil, you probably need bearings and possibly grinding the crankshaft. Cam shaft bearing surfaces, oil pump. .... Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 21, 2015 Author Share Posted October 21, 2015 EA81 engines are pretty bulletproof. Rarely have I seen gasket failures in them. Did you use a Genuine Subaru thermostat? These engines seem to be very sensitive to that. They don't like aftermarket t-stats, so it's Subaru only. You mentioned the temp gauge creeping up past normal. Did you shut down before it reached the top? Perhaps with all the "stuff" you've done so far, there is a new "normal" that's a bit higher than before. If there's no leaking and there's no milky oil, gasket failure just doesn't make sense. Just throwing stuff out there. Please let us know if/when this is resolved. Hey just noticed your profile sez Tahoe..Are you still here? still in tahoe. retired now. gonna part out one of my 84gls as i have the time. thanks for reply. this 84 only has 177k on it so it is worth fixing. i have one with 333k and it still runs great. ya temp creeps up toward the top and then i shut it down. would the definitive test be a compression check? thats next on the list anyway. i agree the bearings and shaft may be scored. not sure how long or far the kid ran it without oil. he was afraid i would yell at him. he didnt tell me for 3 months after the fact so we had no recourse against the oil change place. Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 21, 2015 Author Share Posted October 21, 2015 Intake gasket failure won't cause overheat. Unless you run it long enough to loose too much coolant. My experience has been overheat and you will need to replace headgaskets. Sooner or later, but it is inevitable. Running without oil, you probably need bearings and possibly grinding the crankshaft. Cam shaft bearing surfaces, oil pump. .... ya. now that im retired i have the time. just have so many projects that dont know when i can get around to it. should take out before the snow starts. dont have garage space or puller. was gonna take heads off in frame and lookie see after compression test. Quote Link to comment Share on other sites More sharing options...
DaveT Posted October 21, 2015 Share Posted October 21, 2015 Oh, and piston rings... The headgasket failures I've had were all the small slow stream of bubbles in the overflow reservoir. Those don't show up on a compression test. Another thread on here, pointed out that if you can get a couple of moderately strong people, you can lift the engine out without a hoist or rigging. Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 25, 2015 Author Share Posted October 25, 2015 update today. fan comes on when it is supposed to and ran heater and blower and it blows hot. ran it for 20-30 minutes and it only got up to 185-90 and fan on all the time. let it cool off to add more water to radiator. ( at least half an hr ) restarted. this time heater blew cool air and it started overheating just a couple minutes after fan came on. not sure what is different. as i recall now, my son told me sometimes the heater blew hot and sometimes lukewarm and sometimes cool. is this the t-stat or something else? Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 25, 2015 Share Posted October 25, 2015 update today. fan comes on when it is supposed to and ran heater and blower and it blows hot. ran it for 20-30 minutes and it only got up to 185-90 and fan on all the time. let it cool off to add more water to radiator. ( at least half an hr ) restarted. this time heater blew cool air and it started overheating just a couple minutes after fan came on. not sure what is different. as i recall now, my son told me sometimes the heater blew hot and sometimes lukewarm and sometimes cool. is this the t-stat or something else? I would say start with the thermostat. Get OEM from Subaru. If you are unable to get an OEM for some reason then go with Stant superstat. 180 is the standard temp. Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 25, 2015 Author Share Posted October 25, 2015 thanks. i feel like a dummy sometimes. maybe this should have been 1st on my list. USMB members have bailed out this neophyte several times. thats why i became a gol subscriber. i'll come back with the results. Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 25, 2015 Share Posted October 25, 2015 I would also back flush the cooling system. You can buy radiator flush for about $2 a bottle. Buy two bottles and put them in your radiator and run it for 100-200 miles and then do your back flush. You can get the flush kit, rad flush, and 50/50 antifreeze all at walmart for about $25. After you flush it, replace the Tstat (make sure giggle pin is at the top!) and put the fresh coolant in. Run the engine until it comes up to running temp with the heater on while on a slight incline with the rad cap off. this will burp your cooling system and get rid of any air bubbles. then top off the coolant and you should be ready to rock n' roll Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 25, 2015 Share Posted October 25, 2015 I use Prestone 50/50 with Cor-guard. It claims to have more rust prevention than other brands so theoretically it should be better for our older cooling systems. Also its cheap at only 8-10 dollars a bottle for the 50/50 mix Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 26, 2015 Author Share Posted October 26, 2015 thanks for the suggestions. will definately do. Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 27, 2015 Author Share Posted October 27, 2015 that little bugger , t stat, is not all that easy putting back in. keeps moving so i cant get a good seal between housing and motor. did the ol pan of hot water test and it opened but not as much as the OEM stat i got. keeping fingers crossed. probably get to it tomorrow and test. Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 27, 2015 Share Posted October 27, 2015 What I do is put the t-stat in, then coat both sides of the new gasket with RTV silicon or Right Stuff gasket maker... it helps it stick to the intake manifold and hold that little bugger in there while I get the thermostat housing on. Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 28, 2015 Author Share Posted October 28, 2015 (edited) <p>Sapper</p> <p> </p> <p>your suggestion worked like a charm.</p> <p> </p> <p>both radiator hoses got hot and both heater hoses got hot but heater still blowing cool air. would this suggest temp control on dash?</p> <p> </p> <p>also radiator fan would not come on when temp very slowly inched up past normal. it worked fan 2 days ago. i checked wire plug to radiator. very frustrating.</p> <p> </p> <p>had to shut it down when it started going towards the red mark and water started blowing out the hose attached near the radiator cap.</p> <p> </p> <p>back to square one. if i can get fan to work i may be OK. it doesnt appear to be a head gasket problem. the thermostat appears to working fine.</p> <p> </p> <p>edit. checked fuse. it is fine.</p> Edited October 28, 2015 by roadsubiedog Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 28, 2015 Share Posted October 28, 2015 (edited) Did you follow the instructions on the flush kit? And if so did you get any crap out of the cooling system? Edited October 28, 2015 by Sapper 157 Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 28, 2015 Author Share Posted October 28, 2015 not much. had done previous flush before i parked it. did not get hardly any crap that time either. Quote Link to comment Share on other sites More sharing options...
rdweninger Posted October 28, 2015 Share Posted October 28, 2015 The fan is controlled by a thermoswitch... which completes the ground when radiator water temp hits about 180. So power to fan is always on ... but fan only works when the ground is completed. Easy to test - just take the ground wire (the one from fan to thermoswitch) and ground it. Fan should work then. If not, then check to see if you have 12v power going to fan. Fuse could be blown. If fan works when manually grounded, pull the thermoswitch and clean it. Also a good time to flush the radiator. Possible that water is not getting to the thermoswitch... therefore the switch never grounds. 1 Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 29, 2015 Author Share Posted October 29, 2015 (edited) The fan is controlled by a thermoswitch... which completes the ground when radiator water temp hits about 180. So power to fan is always on ... but fan only works when the ground is completed. Easy to test - just take the ground wire (the one from fan to thermoswitch) and ground it. Fan should work then. If not, then check to see if you have 12v power going to fan. Fuse could be blown. If fan works when manually grounded, pull the thermoswitch and clean it. Also a good time to flush the radiator. Possible that water is not getting to the thermoswitch... therefore the switch never grounds. thats great. i will do that and check back. Edited October 29, 2015 by roadsubiedog Quote Link to comment Share on other sites More sharing options...
roadsubiedog Posted October 29, 2015 Author Share Posted October 29, 2015 The fan is controlled by a thermoswitch... which completes the ground when radiator water temp hits about 180. So power to fan is always on ... but fan only works when the ground is completed. Easy to test - just take the ground wire (the one from fan to thermoswitch) and ground it. Fan should work then. If not, then check to see if you have 12v power going to fan. Fuse could be blown. If fan works when manually grounded, pull the thermoswitch and clean it. Also a good time to flush the radiator. Possible that water is not getting to the thermoswitch... therefore the switch never grounds. well did this and fan works with a ground wire. took out switch and cleaned outside connector and plug. the inside part was clean. then tried it and the fan would not come on. and it slowly overheated again. so i connected a ground wire to run fan all the time. ran it up to temp and an additional 20 minutes and it did NOT overheat! now will take switch off a parts car i have and try that. everything was fine regarding all hoses being hot, heater hoses too but heater still blowing cold air. would this be a bad temperature control on the dash? it's not loose and clicks thru all the ranges. Quote Link to comment Share on other sites More sharing options...
Sapper 157 Posted October 29, 2015 Share Posted October 29, 2015 Almost sounds like you could have a clogged heater core. Theoretically the flushing should have unclogged it but maybe there was so much build up that even that did not help. There should be another member on here who could give extra clarification if that is the problem but that defiantly sounds like a possibility to me. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.