NewfieMJ Posted April 3, 2011 Share Posted April 3, 2011 I just finished installing a new to me 2.5 in the 88 MJ . Fires up , works great , sounds decent but maybe a hair rougher than it should be . I have installed new plugs/cap/rotor/filters/oil and bought a new rad to boot . I filled the rad , and began to bleed to cooling system . Seems I have it circulating to a min point where I get just a hint of heat inside . It did get hot for me at one point , but now , barely warm air . All the hoses are getting hot with the exception to the lower rad hose . I'm building alot of pressure , enough the upper rad hose swells hard , more than normal . If I leave the rad cap off , the water will just flow out , maybe about 10-20 secs after cold starting . Only thing relevant not changed is the t-stat . I would have , I wanted to , but , no stock so I ordered one in . I'm not sure how long this engine sat . Maybe years . If the t-stat was stuck closed , would it have the same effect as I have described or would you say the head gasket is leaking into the water jackets somewhere ? I'm gonna pull the old t-stat out and try running w/o it to see if things change , but , if it doesn't , what's the best way to test the head gasket without pressurizing the combustion chamber ? (have no tool to fit compressor to plug hole) I can't tell if there are bubbles coming out , the rad just overflows . I did initially see some bubbles but figured the system was just burping since it was completely empty . Gone to pull the t-stat , any help is appreciated . This is a project toy , not a DD by any means , no 911 here :wavey: Pics here http://www.jeepforum.com/forum/f53/newf ... a-1189346/ Link to comment Share on other sites More sharing options...
64 Cheyenne Posted April 3, 2011 Share Posted April 3, 2011 I just finished installing a new to me 2.5 in the 88 MJ . Where did you get the 2.5? A reputable source? :agree: On pulling the Tstat. No coolant was in the oil or vice-versa? I would kind of lean towards a bad head gasket. Possibly feel that you picked up somebody else's problem. Link to comment Share on other sites More sharing options...
NewfieMJ Posted April 3, 2011 Author Share Posted April 3, 2011 I got it from a good source . Bring it back if I want . I'd rather not though . He's also willing to pony up for fix parts . No water in the oil that I can tell . But it hasn't been run more than 1 hour total and new oil . Or vice-versa . It was hard to find a replacement for it to be honest . This guy happened to have a few . This jeep was rolled at one point but only 95K (I saw the jeep before and after the engine pull) Compression is good at 130ish straight accross except the #1 is 118 (suspect ?) As for buying someone elses troubles , that comes with any jeep/part , new or used , lol . Link to comment Share on other sites More sharing options...
mnkyboy Posted April 3, 2011 Share Posted April 3, 2011 You could buy a cheap leakdown tester or you could buy an adapter to hook up an air compressor for like $2 Link to comment Share on other sites More sharing options...
NewfieMJ Posted April 3, 2011 Author Share Posted April 3, 2011 You could buy a cheap leakdown tester or you could buy an adapter to hook up an air compressor for like $2 True , but I live 40 miles from the closest source open on Sundays :( . I have confirmed the t-stat was working properly . Gonna try bleeding again I guess . Confirm the pressure build up :hmm: . Never had an issue bleeding a cooling system . I'm pretty sure the head gasket is leaking . :fs1: Link to comment Share on other sites More sharing options...
mnkyboy Posted April 3, 2011 Share Posted April 3, 2011 Do you have a radiator pressure tester? You could pressurize the radiator and see if coolant is leaking into the cylinders Link to comment Share on other sites More sharing options...
kro10000 Posted April 3, 2011 Share Posted April 3, 2011 Easy enough to make an adapter from a spark plug Link to comment Share on other sites More sharing options...
NewfieMJ Posted April 4, 2011 Author Share Posted April 4, 2011 I love jeeps , and sometimes , I hate 'em . Head gasket is fine AFIK . Turns out the YJ has a standard rotaion water pump vs the reverse rotaion water pump on the MJ . I got all the gaskets and stuff to do the head , and ordered a new water pump just because . When I got home I started to pull things off . First off the original engine IE : water pump . Then tore the MJ back down to access the water pump to confirm rotaions . They were opposite :eek: . I didn't know there were different rotation options available on these engines . Well , it sure fits the problems I'm having and should fix things up nicely . Lesson learned . Thanks for the suggestions . :waving: I'll post back tomorrow when the pump is on . I found a 2.5 4WD trans , starter and a 90 insturment cluster(guages) so I'm gonna grab that tomorrow . It's from a 4.0 but I have a seperate tach so I'll leave it on if it don't work properly in the dash . Link to comment Share on other sites More sharing options...
NewfieMJ Posted April 5, 2011 Author Share Posted April 5, 2011 Pump is on . Everything is working as it should . Engine sounds great and the idle is smooth . Cooling system got a new rad , water pump , t-stat and a lower hose . The PO of the truck also had a new clutch fan , and blade . It washed up like new :) . Now I can continue on to something else , there's lots to do with this truck , I have plans Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now