Background: the engine ovreheated a little over a year ago due to water pump failure (replaced pump, thermostat, radiator lid) and I poured some CRC solution in the radiator (says it fixs small hairline fractures in head kinda thing), flushed it out refillled, wroked - no probs.
1 year later: it ran rough, heat guage was fine (halfway), I stopped the car opened the bonnet, the overflow was boiling away, so I turned the heater on for a sec which seemed to calm it down almost immediately. later when it was cool, i checked the radiator (the coolant level was OKiish, no milky residue, i checked the oil, no milky residue. What now? tests etc? possible cause and solution?
You my friend have a blown headgasket, and heres why #1 you have white smoke at start up(this is an indicator of water in the fuel and hence through the exaust when it mixes in the cylinder#2 it goes away after the warm up(this generally happens because the cylinder is so much hot than the boil point of the coolant)very little smoke would be noticed#3 oil on a plug(if they were all of the plugs i would say you had bad valve seals or oil rings on pistons) seeing that it's only one pretty much tells me that is where the gasket is leaking.#4 poor idle(car will idle rough and hesitate because the computer is trying to compensate for the water air fuel mixture. hope this helps please rate this
yes a compression test can be done. If the psi is 30 points difference you will know that it's the head
this is what i would recommend. you need to really pull the engine and do a top to bottom rebuild. here's why.#1 your compression is way low about 40 psi. this could be because your rings are most likely shot.#2 the prescense of oil on the plug so your valve seals are junk as well, probably hard instead of soft like they should be. what alot of people do is only fix the top only or the bottom only but this generally creates more work later on and since you have to pull the heads anyway might as well do it all. this way your engine will last and perform better. As far as type of head gasket I always use FEL-PRO. they have never did me wrong. Remember to get new head bolts as well never use the old ones. also get new exaust bolts as well,trust me on this you will save yourself alot of frustration, rusted exaust bolts never go back in like they should.this over haul is time consuming but well worth it. if you need instyructions i will help you with everything you need to know. I fyour going to do this yourself you can rent some of the specialty tools from Oreilly or Napa and get your money back when you return them. I f you feel that this engine is not worth it your 2 choices then would either buy a reman from the manufacture. this comes with a warrenty(3 year 50,000 mile) or you can get what is called a drop in. This is a motor purchased from a salvage yard and has a 30 day warrenty. it's far cheaper but has it's risks. I have used them in the past and had mixed results. if you go with the drop in just change all the seals and gaskets except for the head and intake. I hope this has give you an idea of what the options are. please rat this and keep me posted............Ron Mueller
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It was idling rough as if it were missing a beat, checked the spark plugs (a couple months old), most were fine, except the 1st plug (cylinder 1 front of engine) which had alittle excess oil which was cleaned up, refitted, engine rerun and no change to the rough idle. Yes, it is dogging under acceleration as well and calms down a little when i take my foot off the gas and coasting. White smoke (no excessive) comes from the exaust on start up, but soon fades once up to operating temp. changing the timing doesn't effect the rough idle.
I didnt know the old 92 sentra had a computer. I suspected the head gasket or a crack in the head and your probably right, but other than strippin it down, is there any last test that would confim your theory? would a compression test do the trick or something else?
cheers buddy, I'll check it ou this weekend.
The compression test results: cyl 1 = 55psi and cyl 2, 3 & 4 = 70 psi
I haven't done a leak down test as I dont have a air compressor, so im not sure if it could be a valve/rings leak or even camshaft/valve train problem. what do ya reckon?
If it is the gasket, a possible cheap fix could be "Steel Seal" or "Thermaggasket" (2 part Elemental Carbon Metallic Alloy Head and Block Repair System). I don't know if you've heard of these products or something similar, they claim 96% success rate. what do you think of them?
Yeah, I realise the psi was pretty low, so I'll have to think about the rebuild for a minute since this was just a $1k run around car thats had a pretty good life considering. thanks for your help, i'll keep you posted ...
can you give me a little more detail. please explain the rough running. was it idling rough? or was it dogging on acceleration? or was it missing? please reply with more details
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